Content creators from the early days when that was a novelty.

Some stuff is legit animation like RWBY, they made the biggest mechinima ever in Red vs Blue, a show made by voicing over video game characters controlled by a player, they made videos showing how to get Xbox achievements called Achievement Hunter, Let's Play with people just doing fun stuff in video games, and then later podcasts with random stuff like people chatting about current topics RT Podcast, plane crashes in Black Box Down, and Austin in ANMA.

A bunch of other stuff too. But that's a good summary I think.