To avoid low quality instructionals I have mainly stuck to these channels. When ever I need to find something I try to find it from these channels first.
Tarik Hopstock – very well structured, short, on point videos with useful details. I mainly study his beginners stuff.
BJJ Globetrotters in Action – (very) long videos of a class of a specific technique (triangle, darce, mount, s-mount, guard passing drills, strangles). I like newer videos by Priit Mihkelson because he shows newer versions of his signature techniques with highly practical implementations. For example I play with his hawking vs back control against rnc, against collar choke, bow and arrow and full crash course of defensive postures etc.
Roy Dean‘s channel
But also Lachlan Giles, Jon Thomas (he stands out for the correct use of microphone 🙂 ), Chewjitsu, Knight Jiu-jitsu, Wiltse Brothers BJJ has some good content (for example this s-mount), BJJ Fanatics with John Danaher, Gordon Ryan and Mickey Musumeci are very good.