I'm going to second TheSwedishTraveler. I know it's difficult to get out of that mindset, but bear in mind that Youtube has a truly enormous following (as does the Internet at large). Chances are, someone else has your own passions, so just make videos about what you like and market them to the people with the same interests.
To take your question at face value, I love gaming videos (but I have favourite channels I watch, and rarely deviate from those unless I'm more interested in the game). With gaming videos I go more for the personality of the gamer and whether they take a reasonably professional approach. If a gamer spends 5 minutes making in-jokes with their buddy that I've no chance of getting, I'll click off and won't come back.
I also like good quality animation videos, music videos, audiobooks, and videos analysing things (I'm loving The Game Theorists at the moment). But that's just me - making videos in those genres won't necessarily bring people flooding to your door. You'll need to make videos about something you're good at and then market it to those people. I don't think there's such a thing as a video genre that you won't need to market. Because of the effort it takes to get an audience, you'll be far better off making videos about something you care about.