OpenChess

Sourceforge, Github, google code...
Besides these there are more.
There are probably 1000 unknown chess engines. You will see engines written in Go, Scala, Haskell, Ruby, you name it.

I wish that somehow there was some sort of central hub to access all of these resources seamlessly. No matter what I do, I imagine somehow that I am missing something important.

There are also some known engines I did not know you could access.
Here is an example:
https://github.com/reul/list