Here's my github page.
I have been contributing to Postgres for long enough that it's tiresome to maintain a list. But I'm especially proud of \ef in psql and PQprepare() in libpq. I also speeded up CRC computations in Postgres 9.5, first by using a faster algorithm and then by using specialised hardware instructions.
I wrote the Postgres protocol dissector for Ethereal (now Wireshark).
I use Ansible at work, and have contributed extensively to the 2.0 release, ranging from typo fixes, to vault improvements, to a complete rewrite of the inventory and hostname parsers, and a rewrite of the SSH connection plugin. I've also written about Ansible.
Arnt Gulbrandsen and I wrote Archiveopteryx, an open-source mail archive server. (The company we founded to develop it, Oryx Mail Systems GmbH, no longer exists, but we still maintain the software in our spare time.)
I'm one of the maintainers of Mojolicious, and I wrote an application framework named Gadwall based on it, for my own use. Here's a list of my other CPAN modules.
(I've removed links to programs I no longer maintain, and there were many things on my old web site that are not here. I'm sorry, I didn't think they were worth reproducing.)