The website https://nobsgames.stavros.io/ helps surface these, and let’s you filter out based on different things.
One that I like in particular is Gauguin. It’s a Sudoku-like with different math-y rules.
Anuto TD is a tower defense game that is also really good, but not so low stress.
Lichess, if you’re into Chess. It’s a great, no compromise, high quality app. Stressful if you get too worked up about competitive, but puzzles are at least relaxing.
Jeremy Parish has less than 100k, and constantly puts out great retrospectives on the nooks and crannies of retro game history.
While the Retronauts podcast he’s involved with is well known, I feel like his YouTube kinda flies under the radar.