Give I have been playing since 1976, I'll be kind and list them horizontally...
RuneQuest, Traveller, Chivalry & Sorcery, Metamorphosis Alpha, Alternity, Gamma World, Star Quest, Star Trek (FASA, LUG, & Decipher), Champions/Heroes, Justice Inc., Shadowrun, Bloodshadows, Shatterzone, Star Wars (D20 and D6), Call of Cthulhu, Pendragon, Kobolds Ate My Baby!, Paranoia, Flashing Blades!, En Garde, Boot Hill, Palladium Fantasy, Tunnels & Trolls, Empire of the Petal Throne, GURPS, The Fantasy Trip (if that counts), Kult, Warhammer FRP, The Riddle of Steel, Over the Edge, Powers & Perils, Nobilis, Og, Mechanical/Dream, TORG, Ars Magica, Golden Heroes, Agone, 7th Sea, Legend of Five Rings, Sengoku, Blue Planet, Jorune, Bushido, Stormbringer, Underworld, Deadlands, Castle Falkenstein, Fading Suns, Cyberpunk, Twilight 2000, Morrow Project, Aftermath, All Flesh Must Be Eaten, Burning Wheel, Dogs in the Vineyard, True20 (if that counts as "non-D&D"), Vampire, Werewolf, Mage, Changeling (these four I mainly played in OWoD; Changeling in NWoD), Hunter, Exalted, Dangerous Journeys, Earthdawn, James Bond RPG, Everway, FUGDE, RISIS, FATE, Spirit of the Century, Harnmaster, Toon, Villains & Vigilantes...
...and for all I know there are a few others, especially if you count the total homebrews that I have played in. Admittedly many of these were only played as a one-shot at a con, but I wanted to give credit where due.
