Recommend to follow these YouTube accounts for a variety of types


Physics
https://www.youtube.com/@tibees/videos
https://www.youtube.com/@AndrewDotsonvideos
https://www.youtube.com/@TheAlmostAstrophysicist
https://www.youtube.com/@KMKPhysics3
https://www.youtube.com/watch?v=IVQ3yH-Zusg
https://www.youtube.com/watch?v=Y9R.....l8TY&t=95s
https://www.youtube.com/@KingCrocoduck

Chemistry
https://www.youtube.com/@zahlazizi


Biology
https://youtu.be/Ez9qK_Htw_0


Computer science
https://www.youtube.com/watch?v=2v1IDsmuv6U

Math major
https://www.youtube.com/@TheMathSorcerer/videos

For the books as a kindle to buy. Recommend to get a schaum's outline, demystified, and the openstax series.

https://www.amazon.com/Anatomy-Phys.....143&sr=8-4

https://www.amazon.com/Schaums-Outl.....142&sr=8-1

Recommend to buy a udemy courses for a self study online and learn from others.
https://www.udemy.com/user/the-math-sorcerer/