Depends on the definition you use here. I could take three games out of a series that's longer than just three games or contains multiple trilogies in one and make quite the list. This discounts a Crash Bandicoot, Mario, Zelda, Metroid, Resident Evil, Professor Layton, Jedi Knight and whatever else. I could take a series where I didn't play all three games and count it anyway, but I won't, which discounts a couple more like Bioshock, Diablo, God of War or Rogue Squadron.
However, taking series that consist of only three consecutive games that I played through to the end, there isn't much.
Basically all that remains that fits the qualification of being a pure trilogy that I played to completion is; Uncharted. Which does happen to be one of my favorites indeed, but soon, it won't count as a trilogy anymore either.







