Primarily video game soundtracks. They're made to play in the background while you perform tasks and come in all sorts of moods / intensity levels.

Favorites:

- FTL

- Crypt of the Necrodancer

- Shatter

- Skyrim

- Deus Ex (all)

- Frozen Synapse

- Mirror's Edge

- Anno (all)

- Civilization (esp. Beyond Earth)

- Transistor and Bastion (skipping vocal tracks)

- Ori, Journey, Flower

Also House, Dubstep, etc., though it's hard to find mixes without vocal tracks.