Oh god damn, buckle up

https://www.youtube.com/@twoswap - awesome math guy

https://www.youtube.com/@alnwlsn - electronics, computers, maker stuff

https://www.youtube.com/@ancientjames - guy builds novel video displays from scratch

https://www.youtube.com/@AppliedScience - flat out smartest guy on he internet

https://www.youtube.com/@Attoparsec - hacky/computery/makey guy

https://www.youtube.com/@ChrisStaecker - math instrument historian, also funny af

https://www.youtube.com/@DiffractionLimited - Build a um scale 3d printer

https://www.youtube.com/@dipdoting - build computer from relays

https://www.youtube.com/@YeanyScience - retired science teacher teaches you science

https://www.youtube.com/@HuygensOptics - turns out you don't know anything about optics, neither do i

https://www.youtube.com/@illinoisenergyprof6878 - learn about atomic power

https://www.youtube.com/@mikeselectricstuff - the original electronics youtuber

https://www.youtube.com/@okooptics - turns out you REALLY dont know anything about optics

https://www.youtube.com/@UsagiElectric - buid computers from the wires up

https://www.youtube.com/@wbeaty - the original science youtuber

Some of these guys rarely upload anymore but the stuff they have uploaded is brilliant. I tried to pick guys who are least likely to show up on the main-stream of recommendations.