Some Let's Plays, some videos about politics, game design, art tutorial stuff, occasionally a documentary. Sometimes it's just silly stuff like that podcast I watched that went over the large majority of the first Harry Potter movie 5 minutes at a time.
I can stay fixed on certain topics but occasionally need to find something new. In that regard it's hard for me to say that I'm definitely watching certain types of videos. Like, I was massively into LPs back in the day but then I had to take a multiple year long break from it. Even now it's basically just one series that I watch, mostly for nostalgia reasons.
How dedicated are you in regards to your hobby?