Animals. Mostly Cats.
Random / Temporary Memes
Double rainbow, David at dentist, ice bucket challenge, autotunes. Very unpredictable. Browsing thru this will show you the breadth.
Vlogs
“YouTubers” with some kind of recurring schtick. Jenna Marbles, Hank Green et al.
Cute Kids
Music Videos
Original versions; parodies; lip dubs and other amateur copies.
Fail videos
Accidents, pranks, car crashes, stupid stunts…
Movies
Clips, remixes, fake trailers, interesting comparisons
Ads
Superimposed at start of most videos, but also popular in their own right
Extreme Sports
GoPro and more.
Parodies
Of popular genres or TV shows…
How To and Tutorials
Basic life skills. Cooking, grooming, make-up…
Academic or Pop Science
TV Clips or Custom Short Form Videos
Product Videos
Haul videos, product reviews & comparisons.
Let’s Play
Gamers playing games.
Extreme Weather
Digital Things! 