Amazing Classic Amiga Project: Custom built 4 port USB Zorro II card
Okay, another in a great line of community-built hardware projects: The Mini-Thylacine, 4 port USB controller card for all Zorro II and Zorro III Amigas.
A few years ago, there was a commercial product called the Thylacine card. The design was eventually open-sourced for anyone who wanted to build it. One Amibay user started making production runs in batches of 20 at a time (Ginny Flick).