This site has a few high quality browser games. The one I come back to is X Type, a bullet hell shoot-em up that has ever expanding enemy ship sizes, and never ends. It gets hard fast.
I also like Xibalba, which is a Doom/Wolfenstein style game playable in the browser.
The creator also did a rewrite of quake in 13 kb of javascript
moonpiedumplings@programming.dev 2 months ago
Swarm Simulator
Open source idle game, playable in browser. No clicking, just watching numbers go up.