I'll agree with everyone else - great idea for a thread!
Most of my subscriptions focus on scratchbuilding terrain, especially the more accessible ones which don't make use of kits or 3d printing. Keeps things within reach for those of us lacking in space and / or finances!
GW-related game names do feature a fair amount but not in an Official GW Products way - scratch building tends to render things unacceptable for a GW store very quickly - and the terrain is pretty generically useful for other sci fi and fantasy settings.
One of my favourite finds has been
Tiny Plastic Killers. Gruff expat gamer living in Japan - sought to create scrap building videos which he might narrate both in English and Japanese since a lot of his Japanese gaming friends were disinterested in English-only channels. I can't seem to find his Japanese versions anymore, but I still enjoy his videos for his unapologetic embracing of a 'good enough for a game' mentality.
LAF's very own
Hobgoblin has a very talented lad -
The RustMonster - whose sculpting and converting puts me to shame despite having nowhere near as many years to practice!
Other channels that I enjoy and have prompted me into scratch building myself:
SJ's Crafting World - sci fi
Hacksaw's Hobby Bunker - sci fi and post apocalyptic
Trihard Games - sci fi and fantasy
Adventures in Crafting - sci fi
Nayfee Paints - sci fi
Alrethian's Crafts & Battles - sci fi and modern
Creatures Caverns & Crafting - sci fi, fantasy and post apocalyptic
And special mention, though he definitely has too many subscribers, for Bill Making Stuff - very much not going for the official GW sponsorship, and entertaining enough in his commentary that the non-gaming Mrs Doodler is happy for it to be beamed onto the main TV to watch.