A few things I’ve done:
In 2017 I needed a haircut and gave a talk about Jane Street’s patch-based code review:
A cheatsheet for uncommonly used bits of OCaml syntax. I made this for interns at Jane Street, but I refer to it myself all the time.
Shell plugin that makes it easier to type English strings on the command line. Read more about it here.
Threaded forum written with a Haskell server and ClojureScript client. In continuous operation since 2014. Used by exactly two people.