| Align | Zip datatypes with non-uniform shapes using These.t |
| Applicative | Applicative functors |
| Clarity_list | List data type |
| Either | Either.t represents value of two exclusive possibilities |
| Fn | Various function combinators |
| Foldable | Foldable signatures |
| Functor | Functors |
| Id | Identity type |
| Monad | Monads |
| Monoid | Monoids |
| Option | Monad instance for an option type |
| Reader | Reader monad |
| Semigroup | Semigroups |
| State | State monad |
| These | Values of two non-exclusive variants |
| Traversable | Traversable signatures |
| Validation | A data-type like Either but with an error-accumulating Applicative |
| Vector | Efficient persistent vectors based on RRB-Trees |
| Void | Void.t is a logically uninhabited data type. |
| Writer | Writer monad |