It's weird, I have a YouTube account as it's part of my Gmail account that I setup when I got a smartphone. However I almost never use that email address nor do I login to YouTube. So even though I watch stuff on YouTube all the time I'm not subscribed to any channel. Every now and then I'll open YouTube and the recommended feed looks really odd, then I realize I'm logged in. It's only when I'm logged out that I get stuff I want to actually see.
The stuff I do watch:
Spooky stories- There are a few channels that have someone narrating stories of either supernatural or true crime, some of these guys even have visuals and sound effects to go with the narration.
Myth and folklore explained- These videos can be 5-10 minutes long upto 45 minutes to an hour. They take myths or legends and then explain the history and lore behind them. Everything from Bigfoot to Cthulu There are even some channels dedicated to exploring the mythos behind movie monsters.
Movie, TV show and video game retrospective reviews- These tend to be long format videos where someone, or a few someone's, will pick a specific film, show or game and spend up to an hour or going over how it was made, the history behind the development, the cultural impact it had and what made it stand out either good or bad.
Science and Nature- I love watching videos like "How fission reactors work" or "we found fossilized remains of an ancient giant turtle". I'm also fascinated by the video that explore ancient civilizations be it vikings, knights, ancient Rome, feudal Japan or the building of the pyramids.
Cooking channels- Lots of cooking channels! I love to cook so it's fun to watch 4 or 5 different chefs make the same dish and see how I can combine and/or incorporate their recipes into mine.
Finance- Of all the stuff I watch on YouTube these are the channels I'm guaranteed to watch alone. Every other video my wife or kids will sit and watch with me. But videos about the stock market, invetments, Federal Reserve policy or the like; everyone comes over to see what has me so fascinated only to roll their eyes and walk away. I do work in Finance so some stuff is important for me to know. Also, it's like with the cooking channels and I'm looking for people who understand personal budgeting and retirement planning better than me and whose ideas I can incorporate.