Mostly puzzle games such as:
- LibreSudoku: Fun Sudoku game with killer Sudoku game mode.
- Braincup: Fun set of short games for improving focus and memory.
- Mental Math: Great way to test your ability to perform math in your head.
EDIT: For relaxing games, I really like Bart Bonte’s collection of color games (red, orange, yellow, green, etc.). They’re quite chill puzzle games with a nice ambience to them.





And it’s always the front-right one too :/