As well as the HIFI/computer stuff mentioned above, I love these;
Techmoan, I’m sure many here will be aware of his channel, lots of retro, odd/quirky/failed but very interesting tech presented in a riveting way by a real nice guy.
Harry’s Garage, founder and ex editor of Evo magazine, interested in all things motoring and a real gent, he’s a mate of James May and some of his cars have actually been featured on Top Gear.
Mighty Car Mods, Even though I’m not the kind of person to race around in a modified (I lie, I daily a MK4 Golf GTI with uprated brakes, suspension, turbo and a remap)... looks stock though. Anyway, I’m a big kid and I love watching their antics and daft humour.
Hoovies Garage, Tyler Hoovies car collection is something to behold, he has penchant for old Mercs but he’s got or has had all kinds of weird and wonderful (or not so wonderful) stuff. He has mixed luck with his purchases but it’s all very entertaining, if sometimes rather sad. He bought a Bentley continental that was a total basket case, a high mileage 996 C4 which blew its engine, he did a Renegade engine conversion which cost more than it would have cost to put an fully rebuilt Porsche engine in, and promptly shat it out on a track... and he bought a beautiful black Ferrari 355 which burst into flames unexpectedly in the hands of another YouTuber... but he doesn’t dwell too much, he just makes content out of it and moves onto the next project.
Tavarish, takes on some ambitious restoration projects and does everything on a budget, the biggest so far being a fire damaged Lamborghini Gallardo with a Twin Turbo conversion, it looked like a total basket case in the beginning but it’s pretty much done now with only a new rear bumper needing to be sprayed and fitted. He’s bought Tyler Hoovies Ferrari 355 to restore, I’ll be amazed if he makes a road worth car from the ashes of that but then, he knows what he’s doing.
Nick Murray, big Porsche enthusiast but an incredibly likeable guy, reviews various cars, helicopters, some fixed wing aircraft, loves dogs and stuffed gorillas, has a cute sister, great taste in music and makes hilarious videos out of hate comments left on his other videos. One of my favourite YouTubers, as much for his likeable personality as his content.
Colin Furze, the deranged plumber... he’s a real life crazy inventor, his videos aren’t massively frequent or even long, but he puts so much work into them, I doubt he could post more than he does. Massively entertaining stuff.