+1 for Freya Holmér, I had skimmed through some explanations on shaders in the past and never really sustained much interest until finding her series. It's been a while since watching but I think the contextualization/demos really helped me understand the big picture of video game graphics
Here are some more mathematics channels:
https://www.youtube.com/user/HarveyMuddCollegeEDU
https://www.youtube.com/c/Aleph0
https://www.youtube.com/c/3blue1brown
Here are some channels on physics:
https://www.youtube.com/c/TenMinutePhysics
https://www.youtube.com/channel/UCPZvrtffxEZ7KZQ9dYCG0xg <- Carver Mead's channel.
Here's something of historical interest: all of the episodes of The Computer Chronicles. https://www.youtube.com/user/ComputerChroniclesYT