I’ve thought about and experimented with it a lot. The main criteria is no lyrics, or at a minimum lyrics in a language you don’t understand at all, since this hijacks attention from parts of the brain useful for programming in a noticeable way. I find prominent fast percussion seems to help with focus but I am less confident of that.

Most other elements don’t seem to matter too much. Baroque, industrial, ambient, etc are all effectively equivalent in most regards.

That said, I tend to lean toward 1990s atmospheric drum-and-bass (pretty much anything released by Good Looking Records) as a good default. That genre maximizes things that seem to help while minimizing things that seem to detract.