Free

RPG's
Basic Fantasy rpg
DCC RPG Quick Start Rules
D&D Free Material
FATE
GURPS Lite
Labyrinth Lord & Mutant Future
Microlite
OpenD6
OSRIC
Tri-Stat dX

System Reference Document Wiki's
BRP SRD
D&D 3.5E SRD
D&D 5E SRD
D20HEROSRD
D20PFSRD
DUNGEON WORLD SRD
FATECORESRD
GUMSHOESRD
THE MODERN PATH SRD
13TH AGE SRD
TRAVELLER SRD
STARFINDER SRD
SWORDS AND WIZARDRY SRD

Miniatures
Heavy Gear Blitz!
Infinity
Mantic Games
Mobile Frame Zero
One Page Rules

Software
TiddlyWiki
Zim