This app was mentioned in 9 comments, with an average of 2.56 upvotes
I believe that all of the following were ported from PC or console releases, except where otherwise noted. Most of these have no IAP or reasonable IAP, except where noted. (Please comment with corrections and I will update.)
I highly recommend picking up a Shield device (K1 tablet or Shield TV) if you want PC-quality games. There's a lot of great exclusives and they typically run from $5 to $15 but rarely have IAP.
Tower Defense
RPGs
Action
Adventure
Point-and-Click
First-person shooters
Top-down Shooters
Strategy
Puzzle
Side-scrollers
One that springs to mind is Anomaly I played a few years back
Kinda late, but Anomaly has its own benchmark they recommend before you play the game.