Pibrella an easy way to play with electronics on your Raspberry Pi.
GitHub - raspberrypi/firmware/boot Boot Firmware files.
NetBSD/evbarm on Raspberry Pi
Raspberry Pi Thin Client project
The Bendyworks Blog - Getting Plan 9 running on the Raspberry Pi
itToby - Using a Raspberry Pi as a Thin Client for RDP/RemoteFX/VMWare View or Citrix
WiringPi is a GPIO access library written in C for the BCM2835 used in the Raspberry Pi. It’s released under the GNU LGPLv3 license and is usable from C and C++ and many other languages with suitable wrappers.
Pi4J a friendly object-oriented I/O API and implementation libraries for Java Programmers to access the full I/O capabilities of the Raspberry Pi platform.
moOde audio player
Runeaudio 2022-06-05: Seems to be dead. Try GitHub - rern/rAudio-1
Max2Play
piCorePlayer
Volumio
Tested to work with RuneAudio_rpi2_rp3_0.4-beta_20160321_2GB.img.
#dtoverlay=hifiberry-dacplus