Assetto Corsa
https://store.steampowered.com/app/244210/Assetto_Corsa/
UI replacement and mod manager - https://assettocorsa.club/content-manager.html 
Reviewer - https://www.youtube.com/watch?v=3g63X4TpO28

Euro Truck Simulator 2
https://store.steampowered.com/app/227300/Euro_Truck_Simulator_2/
Great in-game UI for seat adjustments.

Scania Truck Driving Simulator
https://store.steampowered.com/app/258760/Scania_Truck_Driving_Simulator/
Turn trucks in reverse, drive on a bumpy mountain road etc.

Bleed
https://store.steampowered.com/app/239800/Bleed/
Twin-stick shooting, double jumping and local co-op.
  
Freedom Planet
https://store.steampowered.com/app/248310/Freedom_Planet/
Fun movement, Difficulty settings, Multiple saves

Shovel Knight
https://store.steampowered.com/app/250760/Shovel_Knight_Treasure_Trove/
Hard 2D platforming but unlimited lives and reasonable checkpoints

https://store.steampowered.com/app/543260/Wonder_Boy_The_Dragons_Trap/
Wonder Boy: The Dragon's Trap
Fresh visuals injected into an old 2D platformer adventure.

Star Wars Jedi Knight Jedi Academy
https://store.steampowered.com/app/6020/STAR_WARS_Jedi_Knight__Jedi_Academy/
A not too tough set of fun set pieces.