This is the lockdown generation, so it's also the way to socialize with real world friends.
So that's my answer. Candy Crush.
You mean free game bundled with your OS?
Nokia: Snake
Windows: "3D Pinball for Windows – Space Cadet" or Solitare
TI83: If it was used, hopefully phoenix.
If you want a good EV Nova clone https://endless-sky.github.io/
Roller coaster tycoon: https://github.com/OpenRCT2/OpenRCT2
www.addictinggames.com