| Async | Monadic concurrency library |
| Async_extra | Monadic concurrency library |
| Async_find | Directory traversal with Async |
| Async_inotify | Async wrapper for inotify |
| Async_kernel | Monadic concurrency library |
| Async_parallel | Distributed computing library |
| Async_shell | Shell helpers for Async |
| Async_unix | Monadic concurrency library |
| Bin_prot | A binary protocol generator |
| Core | Industrial strength alternative to OCaml's standard library |
| Core_extended | Extra components that are not as closely vetted or as stable as Core |
| Core_kernel | Industrial strength alternative to OCaml's standard library |
| Fieldslib | Syntax extension to define first class values representing record fields, to get and set record fields, iterate and fold over all fields of a record and create new record values |
| Re2 | OCaml bindings for RE2, Google's regular expression library |
| Sexplib | Library for serializing OCaml values to and from S-expressions |
| Textutils | Text output utilities |
| Type_conv | Library for building type-driven syntax extensions |
| Typerep | typerep is a library for runtime types. |
| Variantslib | Part of Jane Street’s Core library |