Game Sack. It's like Tetris but with retro consoles. Get all the retro consoles in the sack before time runs out as Joe has to start the show! Watch out for copies of Greendog that are trying to block your progress!

Games made by these channels or themed after them?

Lots of civil engineering or construction channels as city builders. Adam Something's would be an interesting one.

Boston Dynamics as a Kerbal-esque robotics game.

Dillongoo as a flashy, well animated action game.

Dropout as some fun party games.

Kurzgesagt would make for great, stylish educational games.

LockPickingLawyer as a sort of half skill half puzzle game.

Modern History as a medieval simulator.

Any tabletop/adventure channel as whatever sort of RPG fits best.

TierZoo as, well, the Earth MMO it already pretends to be.

His passion for all things medieval really goes way beyond that of just being interested in the matter - I tend to show some of his videos to different people and then after a minute or so into the video I stop and tell them "this bloke is a millionaire and owner of Rebellion (Sniper Elite)" - the look on their faces is usually priceless.

Omeleto

I watch a lot of videos from this YT channel because I'm a huge fan of short films (especially since I had four years of Video production where we made short films when I was in high school).

The stories in the Omeleto channel are pretty good made by different teams and production groups - every now and then you'll see people from well known series or Movies.

https://www.youtube.com/omeleto

Edit: Imagine each video being a game, the console would have so many since Omeleto uploads a lot of videos.

Death Battle.

Incidentally, they currently have a Kickstarter campaign running as they're now fully independent.

https://www.kickstarter.com/projects/deathbattle/save-death-battle?ref=profile_backed&category_id=29

Arlo as either a Pikmin-type game or a Classic Paper Mario-type RPG.

I think if you made the Lock picking lawyer into a puzzle game you could make it really hard. I would play a difficult lock picking puzzle game.