Console-specific development wikis
Here's a list of wikis dedicated to hosting documentation regarding console hardware and development. Useful for those interested in coding homebrew software.
Consoles[edit]
NESdev (NES)
SNESdev (Super Nintendo)
SNES Development Wiki (Super Nintendo)
MegaDrive Development Wiki (Sega Genesis/Mega Drive and add-ons)
Archaic Pixels (PC Engine/TurboGrafx-16, add-ons, and PC-FX)
MSX Assembly (MSX)
SMS Power (Sega Master System, SG-1000, SC-3000, SF-7000. Game Gear)
Saturn documentation (Sega Saturn)
Nocash Playstation specifications
PS2 Developer Wiki (PlayStation 2)
GC-Forever (GameCube)
PS3 Developer Wiki (PlayStation 3)
Wiibrew (Wii)
WiiUbrew (Wii U)
xboxdevwiki (Xbox)
Handhelds[edit]
GBdev (Game Boy/Game Boy Color)
PlanetVB Wiki (Virtual Boy)
GBAdev (Game Boy Advance) (not really a wiki, but it was the best resource I could find)
DS Wiki Archive (Nintendo DS)
NDSTech Archive (Nintendo DS)
3Dbrew (Nintendo 3DS)