I can recommend dub techno for coding, works a treat for me at least. Nice and steady, relatively fast tempo but not too aggressive or intrusive. And crucially, no lyrics, which I find distracting when coding or writing.
Yes. The paper found 2.4 Hz frequencies to be the secret sauce which is 144 BPM and in pystrance/goa range. I would guess that is common freq range for lfos and modulations as well.
Not an artist per se but the app Endel is this continuous generated music with different "scenarios" for... well... different scenarios. IMO the full continuity is a game changer for focus.