A quick grep would seem to indicate:
- unix because I find low-level solutions to big problems can be more reliable than fancy ones.
- lablgl because I love using OpenGL for visualization and this tried-and-tested library is rock solid.
- uri is indispensable in the web age.
- yojson because JSON is everywhere and this library is super simple and super fast.
- ppx_deriving but I really wish OCaml had generic printing!
Honorable mentions go to lwt and cohttp, both of which are awsome but I don’t use them often enough to make the top 5.