In particular order:
Trials Rising (Xbone)
NBA Jam (Xbox 360)
NFL Blitz (Xbox 360)
3 on 3 NHL Arcade (Xbox 360)
Super Mega Baseball 2 (Xbone)
Tecmo Super Bowl (NES)
GeneRally (PC)
Battlefield Bad Company (Xbox 360)
rFactor 2 (PC)
Forza Horizon 4 (PC version)
I still have my 360 hooked up so I can play NFL Blitz and 3 on 3 NHL Arcade. I have over 500 hours in Trials Fusion, no idea what my total hours would be if all of the games in that series were combined but it's probably well over 1,000 hours.
The rest are ones I come back to from time to time. I typically play through the AAA games once and never go back to them.
Honorable mention are River Raid and Chopper Command.