Adafruit - new stuff they sell, and tutorials that are fun.
TheCrafsman - a puppet learning how to craft, 3d print, mold, etc.
Bitluni's Lab - https://www.youtube.com/user/bitlunislab elaborate and funny tutorial videos about building gadgets.
Branchus Creations - board level repair for older PC's and gadgets https://www.youtube.com/c/BranchusCreations/featured
Choll W. Kim - Laser spine surgery and info https://www.youtube.com/c/ChollKimMDPhDSanDiego/about
David Bull - https://www.youtube.com/user/seseragistudio/ Tokyo-based woodblock printmaker, video presentations of his work, including a number of videos showing the complete process of making his prints.
Devoxx - developer tech events, talks, presentations https://www.youtube.com/c/Devoxx2015
Electronics Repair School - https://www.youtube.com/channel/UCooKQlg-HZ0PFAPc4Ymg3RA
Evil Ted - visual effects, prop., modelmaking from a pro.. https://www.youtube.com/user/evilted40
HomoFaciens - maker, elecronics https://www.youtube.com/c/HomoFaciens/videos
Jeremy Fielding - home engineering, learning, motors, robotics, making https://www.youtube.com/channel/UC_SLthyNX_ivd-dmsFgmJVg
Just A Printer - behind the scenes, explantation, at a small printing business https://www.youtube.com/channel/UCSuSPbvmwLZv9CMdeSsWkFA
Just have a think - Climate and Sustainable Energy, Technology discussion, education https://www.youtube.com/c/JustHaveaThink/videos
Kens Karpentry - garage builder, explains process, business https://www.youtube.com/user/ken311953
NorthRidgeFix - electronics repair. Often fixes without schematics, explains diagnosing and tracing faults. https://www.youtube.com/channel/UCLaXgfNlVxY149shiA1pykQ
SixtySymbols - cool videos about physics and astronomy https://www.youtube.com/user/sixtysymbols
Stock Markets With Bruce
The Signal Path - electronics tear down, analysis, and repair. https://www.youtube.com/user/TheSignalPathBlog
Two Minute Papers - video summary of interesting or exciting CompSci papers https://www.youtube.com/user/keeroyz