Personally I’ve played a hell of a lot of HexArena. Just a simple, low intensity game that runs well and is maintained :))
And before anyone says it, chess and go are great browser games!
I’ve been an avid player at https://snake.io/ for years now. What I love about this game is because you customize your skins which is something that I love. This game is certainly an all time favorite of mine.
https://snake.io/ is definitely the browser game that took a lot of my time but I’m having a lot of fun playing it.
I’ve played alot of paperclips in classes, it just looks like a random website but it’s a really fun idle clicker thingy it’s at https://www.decisionproblem.com/paperclips/index2.html
On the topic of idle games, Cookie Clicker and A Dark Room still hold up well.
Dark room?
Its a somewhat more story and gameplay focused than Cookie Clicker, but still pretty chill. I won’t say too much more, considering that it’d just spoil the fun of discovery.