Big beat and trip hop mixes mostly. Right now I'm listening to https://www.youtube.com/watch?v=nubJdAfAElk. More because they're good for drowning out office background noise without being distracting than anything else though. If I'm the only person in my office I code in silence.
https://work.endel.io/ got posted to HN this week. "Endel is an audio app that helps you create the perfect sound environment for work or relaxation." It's a prototype with a single play list afaik https://news.ycombinator.com/item?id=16797089