I haven't played anything from the following franchises: Legend of Zelda, The Witcher, Mass Effect, Diablo, Soulsborne, Command & Conquer, Age of Empires, Civilization, Metroid, GTA, RDR, COD, Battlefield, and probably plenty more.

Then there are all the 'iconic' standalone games I haven't touched, but I don't think we have time for that list.