"OUTSIDE IN" -- a classic, if you were memorised by Flatland (2007) as a child you'll love the majority of these videos, but mainly "outside in" (and "4d Toys" but we'll get to that later.) This video is a recent upscale and has the credits in it (!!!) unlike many others. Also! in the description theres a lot of information about its production! (and the voices' names! which i think is pretty cool!)
before this video was made i used to watch the 2-part video called "how to theoredically turn a sphere inside out", which, looking back, is pretty bad quality, but! the dialouge and information is the same.

A gobou video! Their stuff is always really really good (+ always yume nikki themed!) When i first watched this one i got the song stuck in my head for weeks! Not much to say other than their manipulation of pixels to music is as impresive as always!

"4D Toys" -- a really neat visulization (+ explanation) of 4D objects in 3D space! Reminds me a lot of Flatland (2007) because of that.

"W" -- Jan Misali's videos are really good, always. however, I do tend to like their "one off" videos more. (although his con-lang series is really cool as well) This video (along with "there are 48 regular polyhedra") is probably my favorite out of all of them!

LLP's videos are always really really good! what more could a person want then seeing a lock be roasted for 1 to 3 minutes?

Non-euclidean space is really, really, really cool, and this is a really cool "easy to understand" video about it!

"The Universe in a Nutshell" -- This video is a bit outdated, since string theory ended up not working in 3 dimentions (it does work in 6 dimentions for some reason), regardless its a super interesting overview on important theoredical (and practical) physic theories!