| Async | Monadic concurrency library |
| Async_extended | Additional utilities for async |
| 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_smtp | SMTP client and server |
| Async_ssl | An Async-pipe-based interface with OpenSSL. |
| Async_unix | Monadic concurrency library |
| Bin_prot | A binary protocol generator |
| Comparelib | Part of Jane Street’s Core library |
| Core | Industrial strength alternative to OCaml's standard library |
| Core_bench | Benchmarking 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 |
| Ctypes | Combinators for binding to C libraries without writing any C. |
| Custom_printf | Extension for printf format strings |
| Email_message | E-mail message parser |
| Enumerate | Quotation expanders for enumerating finite types. |
| Faillib | Part of Jane Street’s Core 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 |
| Herelib | Part of Jane Street’s Core library |
| Jenga | Build system |
| Ocaml_plugin | Automatically build and dynlink OCaml source files |
| Pa_bench | Syntax extension for inline benchmarks |
| Pa_ounit | Syntax extension for oUnit |
| Pa_test | Quotation expander for assertions. |
| Patdiff | File Diff using the Patience Diff algorithm |
| Patience_diff | Diff library using Bram Cohen's patience diff algorithm. |
| Pipebang | Part of Jane Street’s Core library |
| 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 |
| Typehashlib | Part of Jane Street’s Core library |
| Typerep | typerep is a library for runtime types. |
| Variantslib | Part of Jane Street’s Core library |