I play a lot of games with my 6yo, our top suggestions:

1. Chuchel (point&click about a funny creature in pursuit of a cherry)

2. Donut County (drop things into a hole that gets bigger)

3. The Henry Stickmin Collection (classic multiple choice 2D animated Flash game extended, funny)

4. Superliminal (very imaginative space distortion puzzle, adult help needed)