diff --git a/add_integers.uplc b/add_integers.uplc
index f7b7ffab..bb78578c 100644
--- a/add_integers.uplc
+++ b/add_integers.uplc
@@ -1,5 +1,5 @@
 (program
   1.0.0
-  [ (builtin divideInteger) (con integer 5) (con integer 2) ]
+  [ (builtin remainderInteger) (con integer 5) (con integer 2)]
 )
 
diff --git a/crates/uplc/src/machine.rs b/crates/uplc/src/machine.rs
index 48d59807..3521b12d 100644
--- a/crates/uplc/src/machine.rs
+++ b/crates/uplc/src/machine.rs
@@ -450,7 +450,9 @@ impl Value {
                 Constant::String(s) => s.chars().count() as i64,
                 Constant::Unit => 1,
                 Constant::Bool(_) => 1,
-                Constant::ProtoList(_, _) => todo!(),
+                Constant::ProtoList(_, items) => items.iter().fold(0, |acc, constant| {
+                    acc + Value::Con(constant.clone()).to_ex_mem()
+                }),
                 Constant::ProtoPair(_, _, _, _) => todo!(),
                 Constant::Data(_) => todo!(),
             },
@@ -461,17 +463,49 @@ impl Value {
     }
 
     pub fn expect_type(&self, r#type: Type) -> Result<(), Error> {
-        match self {
-            Value::Con(constant) => {
-                let constant_type = Type::from(constant);
+        let constant: Constant = self.clone().try_into()?;
 
-                if constant_type == r#type {
-                    Ok(())
-                } else {
-                    Err(Error::TypeMismatch(r#type, constant_type))
-                }
-            }
-            rest => Err(Error::NotAConstant(rest.clone())),
+        let constant_type = Type::from(&constant);
+
+        if constant_type == r#type {
+            Ok(())
+        } else {
+            Err(Error::TypeMismatch(r#type, constant_type))
+        }
+    }
+
+    pub fn expect_list(&self) -> Result<(), Error> {
+        let constant: Constant = self.clone().try_into()?;
+
+        let constant_type = Type::from(&constant);
+
+        if matches!(constant_type, Type::List(_)) {
+            Ok(())
+        } else {
+            Err(Error::ListTypeMismatch(constant_type))
+        }
+    }
+}
+
+impl TryFrom<Value> for Type {
+    type Error = Error;
+
+    fn try_from(value: Value) -> Result<Self, Self::Error> {
+        let constant: Constant = value.try_into()?;
+
+        let constant_type = Type::from(&constant);
+
+        Ok(constant_type)
+    }
+}
+
+impl TryFrom<Value> for Constant {
+    type Error = Error;
+
+    fn try_from(value: Value) -> Result<Self, Self::Error> {
+        match value {
+            Value::Con(constant) => Ok(constant),
+            rest => Err(Error::NotAConstant(rest)),
         }
     }
 }
diff --git a/crates/uplc/src/machine/cost_model.rs b/crates/uplc/src/machine/cost_model.rs
index 9211cfff..143a7f4c 100644
--- a/crates/uplc/src/machine/cost_model.rs
+++ b/crates/uplc/src/machine/cost_model.rs
@@ -572,9 +572,36 @@ impl BuiltinCosts {
                     .cpu
                     .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
             },
-            DefaultFunction::QuotientInteger => todo!(),
-            DefaultFunction::RemainderInteger => todo!(),
-            DefaultFunction::ModInteger => todo!(),
+            DefaultFunction::QuotientInteger => ExBudget {
+                mem: self
+                    .quotient_integer
+                    .mem
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+                cpu: self
+                    .quotient_integer
+                    .cpu
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+            },
+            DefaultFunction::RemainderInteger => ExBudget {
+                mem: self
+                    .remainder_integer
+                    .mem
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+                cpu: self
+                    .remainder_integer
+                    .cpu
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+            },
+            DefaultFunction::ModInteger => ExBudget {
+                mem: self
+                    .mod_integer
+                    .mem
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+                cpu: self
+                    .mod_integer
+                    .cpu
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+            },
             DefaultFunction::EqualsInteger => ExBudget {
                 mem: self
                     .equals_integer
@@ -770,10 +797,28 @@ impl BuiltinCosts {
             DefaultFunction::FstPair => todo!(),
             DefaultFunction::SndPair => todo!(),
             DefaultFunction::ChooseList => todo!(),
-            DefaultFunction::MkCons => todo!(),
-            DefaultFunction::HeadList => todo!(),
-            DefaultFunction::TailList => todo!(),
-            DefaultFunction::NullList => todo!(),
+            DefaultFunction::MkCons => ExBudget {
+                mem: self
+                    .mk_cons
+                    .mem
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+                cpu: self
+                    .mk_cons
+                    .cpu
+                    .cost(args[0].to_ex_mem(), args[1].to_ex_mem()),
+            },
+            DefaultFunction::HeadList => ExBudget {
+                mem: self.head_list.mem.cost(args[0].to_ex_mem()),
+                cpu: self.head_list.cpu.cost(args[0].to_ex_mem()),
+            },
+            DefaultFunction::TailList => ExBudget {
+                mem: self.tail_list.mem.cost(args[0].to_ex_mem()),
+                cpu: self.tail_list.cpu.cost(args[0].to_ex_mem()),
+            },
+            DefaultFunction::NullList => ExBudget {
+                mem: self.null_list.mem.cost(args[0].to_ex_mem()),
+                cpu: self.null_list.cpu.cost(args[0].to_ex_mem()),
+            },
             DefaultFunction::ChooseData => todo!(),
             DefaultFunction::ConstrData => todo!(),
             DefaultFunction::MapData => todo!(),
diff --git a/crates/uplc/src/machine/error.rs b/crates/uplc/src/machine/error.rs
index 5840ad47..cd789dcb 100644
--- a/crates/uplc/src/machine/error.rs
+++ b/crates/uplc/src/machine/error.rs
@@ -22,6 +22,10 @@ pub enum Error {
     NonFunctionalApplication(Value),
     #[error("Type mismatch expected '{0}' got '{1}'")]
     TypeMismatch(Type, Type),
+    #[error("Type mismatch expected '(list a)' got '{0}'")]
+    ListTypeMismatch(Type),
+    #[error("Empty List:\n\n{0:#?}")]
+    EmptyList(Value),
     #[error("A builtin received a term argument when something else was expected:\n\n{0}\n\nYou probably forgot to wrap the builtin with a force.")]
     UnexpectedBuiltinTermArgument(Term<NamedDeBruijn>),
     #[error("A builtin expected a term argument, but something else was received:\n\n{0}\n\nYou probably have an extra force wrapped around a builtin")]
@@ -36,4 +40,8 @@ pub enum Error {
     ByteStringOutOfBounds(isize, Vec<u8>),
     #[error("Divide By Zero\n\n{0} / {1}")]
     DivideByZero(isize, isize),
+    #[error("Ed25519S PublicKey should be 32 bytes but it was {0}")]
+    UnexpectedEd25519PublicKeyLength(usize),
+    #[error("Ed25519S Signature should be 64 bytes but it was {0}")]
+    UnexpectedEd25519SignatureLength(usize),
 }
diff --git a/crates/uplc/src/machine/runtime.rs b/crates/uplc/src/machine/runtime.rs
index 4dedbb53..bdf819c8 100644
--- a/crates/uplc/src/machine/runtime.rs
+++ b/crates/uplc/src/machine/runtime.rs
@@ -76,9 +76,9 @@ impl DefaultFunction {
             DefaultFunction::SubtractInteger => 2,
             DefaultFunction::MultiplyInteger => 2,
             DefaultFunction::DivideInteger => 2,
-            DefaultFunction::QuotientInteger => todo!(),
-            DefaultFunction::RemainderInteger => todo!(),
-            DefaultFunction::ModInteger => todo!(),
+            DefaultFunction::QuotientInteger => 2,
+            DefaultFunction::RemainderInteger => 2,
+            DefaultFunction::ModInteger => 2,
             DefaultFunction::EqualsInteger => 2,
             DefaultFunction::LessThanInteger => 2,
             DefaultFunction::LessThanEqualsInteger => 2,
@@ -106,10 +106,10 @@ impl DefaultFunction {
             DefaultFunction::FstPair => todo!(),
             DefaultFunction::SndPair => todo!(),
             DefaultFunction::ChooseList => todo!(),
-            DefaultFunction::MkCons => todo!(),
-            DefaultFunction::HeadList => todo!(),
-            DefaultFunction::TailList => todo!(),
-            DefaultFunction::NullList => todo!(),
+            DefaultFunction::MkCons => 2,
+            DefaultFunction::HeadList => 1,
+            DefaultFunction::TailList => 1,
+            DefaultFunction::NullList => 1,
             DefaultFunction::ChooseData => todo!(),
             DefaultFunction::ConstrData => todo!(),
             DefaultFunction::MapData => todo!(),
@@ -135,9 +135,9 @@ impl DefaultFunction {
             DefaultFunction::SubtractInteger => 0,
             DefaultFunction::MultiplyInteger => 0,
             DefaultFunction::DivideInteger => 0,
-            DefaultFunction::QuotientInteger => todo!(),
-            DefaultFunction::RemainderInteger => todo!(),
-            DefaultFunction::ModInteger => todo!(),
+            DefaultFunction::QuotientInteger => 0,
+            DefaultFunction::RemainderInteger => 0,
+            DefaultFunction::ModInteger => 0,
             DefaultFunction::EqualsInteger => 0,
             DefaultFunction::LessThanInteger => 0,
             DefaultFunction::LessThanEqualsInteger => 0,
@@ -165,10 +165,10 @@ impl DefaultFunction {
             DefaultFunction::FstPair => todo!(),
             DefaultFunction::SndPair => todo!(),
             DefaultFunction::ChooseList => todo!(),
-            DefaultFunction::MkCons => todo!(),
-            DefaultFunction::HeadList => todo!(),
-            DefaultFunction::TailList => todo!(),
-            DefaultFunction::NullList => todo!(),
+            DefaultFunction::MkCons => 1,
+            DefaultFunction::HeadList => 1,
+            DefaultFunction::TailList => 1,
+            DefaultFunction::NullList => 1,
             DefaultFunction::ChooseData => todo!(),
             DefaultFunction::ConstrData => todo!(),
             DefaultFunction::MapData => todo!(),
@@ -194,9 +194,9 @@ impl DefaultFunction {
             DefaultFunction::SubtractInteger => arg.expect_type(Type::Integer),
             DefaultFunction::MultiplyInteger => arg.expect_type(Type::Integer),
             DefaultFunction::DivideInteger => arg.expect_type(Type::Integer),
-            DefaultFunction::QuotientInteger => todo!(),
-            DefaultFunction::RemainderInteger => todo!(),
-            DefaultFunction::ModInteger => todo!(),
+            DefaultFunction::QuotientInteger => arg.expect_type(Type::Integer),
+            DefaultFunction::RemainderInteger => arg.expect_type(Type::Integer),
+            DefaultFunction::ModInteger => arg.expect_type(Type::Integer),
             DefaultFunction::EqualsInteger => arg.expect_type(Type::Integer),
             DefaultFunction::LessThanInteger => arg.expect_type(Type::Integer),
             DefaultFunction::LessThanEqualsInteger => arg.expect_type(Type::Integer),
@@ -260,10 +260,18 @@ impl DefaultFunction {
             DefaultFunction::FstPair => todo!(),
             DefaultFunction::SndPair => todo!(),
             DefaultFunction::ChooseList => todo!(),
-            DefaultFunction::MkCons => todo!(),
-            DefaultFunction::HeadList => todo!(),
-            DefaultFunction::TailList => todo!(),
-            DefaultFunction::NullList => todo!(),
+            DefaultFunction::MkCons => {
+                if args.is_empty() {
+                    Ok(())
+                } else {
+                    let first = args[0].clone();
+
+                    arg.expect_type(Type::List(Box::new(first.try_into()?)))
+                }
+            }
+            DefaultFunction::HeadList => arg.expect_list(),
+            DefaultFunction::TailList => arg.expect_list(),
+            DefaultFunction::NullList => arg.expect_list(),
             DefaultFunction::ChooseData => todo!(),
             DefaultFunction::ConstrData => todo!(),
             DefaultFunction::MapData => todo!(),
@@ -318,9 +326,44 @@ impl DefaultFunction {
                 }
                 _ => unreachable!(),
             },
-            DefaultFunction::QuotientInteger => todo!(),
-            DefaultFunction::RemainderInteger => todo!(),
-            DefaultFunction::ModInteger => todo!(),
+            DefaultFunction::QuotientInteger => match (&args[0], &args[1]) {
+                (Value::Con(Constant::Integer(arg1)), Value::Con(Constant::Integer(arg2))) => {
+                    if *arg2 != 0 {
+                        let ret = (*arg1 as f64) / (*arg2 as f64);
+
+                        let ret = if ret < 0. { ret.ceil() } else { ret.floor() };
+
+                        Ok(Value::Con(Constant::Integer(ret as isize)))
+                    } else {
+                        Err(Error::DivideByZero(*arg1, *arg2))
+                    }
+                }
+                _ => unreachable!(),
+            },
+            DefaultFunction::RemainderInteger => match (&args[0], &args[1]) {
+                (Value::Con(Constant::Integer(arg1)), Value::Con(Constant::Integer(arg2))) => {
+                    if *arg2 != 0 {
+                        let ret = arg1 % arg2;
+
+                        Ok(Value::Con(Constant::Integer(ret)))
+                    } else {
+                        Err(Error::DivideByZero(*arg1, *arg2))
+                    }
+                }
+                _ => unreachable!(),
+            },
+            DefaultFunction::ModInteger => match (&args[0], &args[1]) {
+                (Value::Con(Constant::Integer(arg1)), Value::Con(Constant::Integer(arg2))) => {
+                    if *arg2 != 0 {
+                        let ret = arg1 % arg2;
+
+                        Ok(Value::Con(Constant::Integer(ret.abs())))
+                    } else {
+                        Err(Error::DivideByZero(*arg1, *arg2))
+                    }
+                }
+                _ => unreachable!(),
+            },
             DefaultFunction::EqualsInteger => match (&args[0], &args[1]) {
                 (Value::Con(Constant::Integer(arg1)), Value::Con(Constant::Integer(arg2))) => {
                     Ok(Value::Con(Constant::Bool(arg1 == arg2)))
@@ -461,11 +504,25 @@ impl DefaultFunction {
             },
             DefaultFunction::VerifyEd25519Signature => match (&args[0], &args[1], &args[2]) {
                 (
-                    Value::Con(Constant::ByteString(_arg1)),
-                    Value::Con(Constant::ByteString(_arg2)),
-                    Value::Con(Constant::ByteString(_arg3)),
+                    Value::Con(Constant::ByteString(public_key)),
+                    Value::Con(Constant::ByteString(message)),
+                    Value::Con(Constant::ByteString(signature)),
                 ) => {
-                    todo!()
+                    use cryptoxide::ed25519;
+
+                    let public_key: [u8; 32] = public_key
+                        .clone()
+                        .try_into()
+                        .map_err(|e: Vec<u8>| Error::UnexpectedEd25519PublicKeyLength(e.len()))?;
+
+                    let signature: [u8; 64] = signature
+                        .clone()
+                        .try_into()
+                        .map_err(|e: Vec<u8>| Error::UnexpectedEd25519SignatureLength(e.len()))?;
+
+                    let valid = ed25519::verify(message, &public_key, &signature);
+
+                    Ok(Value::Con(Constant::Bool(valid)))
                 }
                 _ => unreachable!(),
             },
@@ -524,10 +581,44 @@ impl DefaultFunction {
             DefaultFunction::FstPair => todo!(),
             DefaultFunction::SndPair => todo!(),
             DefaultFunction::ChooseList => todo!(),
-            DefaultFunction::MkCons => todo!(),
-            DefaultFunction::HeadList => todo!(),
-            DefaultFunction::TailList => todo!(),
-            DefaultFunction::NullList => todo!(),
+            DefaultFunction::MkCons => match (&args[0], &args[1]) {
+                (Value::Con(item), Value::Con(Constant::ProtoList(r#type, list))) => {
+                    let mut ret = vec![item.clone()];
+                    ret.extend(list.clone());
+
+                    Ok(Value::Con(Constant::ProtoList(r#type.clone(), ret)))
+                }
+                _ => unreachable!(),
+            },
+            DefaultFunction::HeadList => match &args[0] {
+                c @ Value::Con(Constant::ProtoList(_, list)) => {
+                    if list.is_empty() {
+                        Err(Error::EmptyList(c.clone()))
+                    } else {
+                        Ok(Value::Con(list[0].clone()))
+                    }
+                }
+                _ => unreachable!(),
+            },
+            DefaultFunction::TailList => match &args[0] {
+                c @ Value::Con(Constant::ProtoList(r#type, list)) => {
+                    if list.is_empty() {
+                        Err(Error::EmptyList(c.clone()))
+                    } else {
+                        Ok(Value::Con(Constant::ProtoList(
+                            r#type.clone(),
+                            list[1..].to_vec(),
+                        )))
+                    }
+                }
+                _ => unreachable!(),
+            },
+            DefaultFunction::NullList => match &args[0] {
+                Value::Con(Constant::ProtoList(_, list)) => {
+                    Ok(Value::Con(Constant::Bool(list.is_empty())))
+                }
+                _ => unreachable!(),
+            },
             DefaultFunction::ChooseData => todo!(),
             DefaultFunction::ConstrData => todo!(),
             DefaultFunction::MapData => todo!(),
diff --git a/crates/uplc/src/pretty.rs b/crates/uplc/src/pretty.rs
index 94461883..06b18fa2 100644
--- a/crates/uplc/src/pretty.rs
+++ b/crates/uplc/src/pretty.rs
@@ -1,7 +1,7 @@
 use pretty::RcDoc;
 
 use crate::{
-    ast::{Constant, Program, Term},
+    ast::{Constant, Program, Term, Type},
     flat::Binder,
 };
 
@@ -170,9 +170,65 @@ impl Constant {
             Constant::Bool(b) => RcDoc::text("bool")
                 .append(RcDoc::line())
                 .append(RcDoc::text(if *b { "True" } else { "False" })),
-            Constant::ProtoList(_, _) => todo!(),
+            Constant::ProtoList(r#type, items) => RcDoc::text("(")
+                .append(
+                    RcDoc::text("list")
+                        .append(RcDoc::line())
+                        .append(r#type.to_doc()),
+                )
+                .append(RcDoc::line_())
+                .append(RcDoc::text(")"))
+                .append(RcDoc::line())
+                .append(RcDoc::text("["))
+                .append(RcDoc::intersperse(
+                    items.iter().map(|c| c.to_doc_list()),
+                    RcDoc::text(","),
+                ))
+                .append(RcDoc::text("]")),
+            Constant::ProtoPair(_, _, _, _) => todo!(),
+            Constant::Data(_) => todo!(),
+        }
+    }
+
+    fn to_doc_list(&self) -> RcDoc<()> {
+        match self {
+            Constant::Integer(i) => RcDoc::as_string(i),
+            Constant::ByteString(bs) => RcDoc::text("#").append(RcDoc::text(hex::encode(bs))),
+            Constant::String(s) => RcDoc::text("\"")
+                .append(RcDoc::text(s))
+                .append(RcDoc::text("\"")),
+            Constant::Unit => RcDoc::text("()"),
+            Constant::Bool(b) => RcDoc::text(if *b { "True" } else { "False" }),
+            Constant::ProtoList(_, items) => RcDoc::text("[")
+                .append(RcDoc::intersperse(
+                    items.iter().map(|c| c.to_doc_list()),
+                    RcDoc::text(","),
+                ))
+                .append(RcDoc::text("]")),
             Constant::ProtoPair(_, _, _, _) => todo!(),
             Constant::Data(_) => todo!(),
         }
     }
 }
+
+impl Type {
+    fn to_doc(&self) -> RcDoc<()> {
+        match self {
+            Type::Bool => RcDoc::text("bool"),
+            Type::Integer => RcDoc::text("integer"),
+            Type::String => RcDoc::text("string"),
+            Type::ByteString => RcDoc::text("bytestring"),
+            Type::Unit => RcDoc::text("unit"),
+            Type::List(r#type) => RcDoc::text("(")
+                .append(
+                    RcDoc::text("list")
+                        .append(RcDoc::line())
+                        .append(r#type.to_doc()),
+                )
+                .append(RcDoc::line_())
+                .append(RcDoc::text(")")),
+            Type::Pair(_, _) => todo!(),
+            Type::Data => todo!(),
+        }
+    }
+}