Hm. I need help finding a game to play that is somewhat brainless (puzzle games?), ideally windowed where sound is of secondary importance so I have something to do while I watch/listen to youtube videos.
I watch/listen to alot of youtube videos myself while gaming. Here are a few titles that I tend to gravitate toward when catching up on podcasts and the like:
Viscera Cleanup Detail (Early Access, but nearly finished)
Subnautica (Early Access - still very rough around the edges and far from being feature complete)
Starbound (Early Access - also far from being feature complete, but very playable in its current state)
Starbound and Subnautica might require some time to figure out (there are wikis that can help you out) but once you know what you're doing, they're fairly mindless.
Old school first-person shooters (
Doom,
Quake,
Serious Sam,
Shadow Warrior), turn-based strategy games (
Civilization,
Galactic Civilizations), certain roguelikes (
The Binding of Isaac,
Don't Starve,
Darkest Dungeon) and city management games (
Cities: Skylines) sometimes fit the bill for me as well. YMMV depending on how well you multitask.
Sorry I can't rec any
actual puzzle games. Not really my genre. I don't know if any of these will suit you but if not, perhaps they'll at least point you in the right direction.
Good luck - oh, and if you have questions about any of these games, just ask.
... I guess that was more than a "few" titles. Oops.