This is a great general electronics channel, with reviews of multimeters, oscilloscopes, and related equipment.
James is building a piplined TTL computer that is much more complex and interesting than mine.
Julian's is another general electronics channel, but he does a lot of PCB work and is also building a TTL computer.
Ben's channel is famous, and the inspiration for a lot of people building TTL based computers. He goes into great detail, which makes it easy for anyone to follow.
Daniel's channel is more about Linux shells than electronics, but he is building his own breadboard computer.
David is building a Ben Eater inspired breadboard computer, but he also has other electronics videos... including 74LS181 breadboard tests.
John Philip Jones
This channel is not actively updated, but contains numerous helpful electronics lessons, programming in python, etc.