I love solo piano music. Especially for focussed work, it's exactly the kind of music that is interesting and stimulating, but humble enough to remain in the background and not requiring me to exclusively listen to it.
The only thing I find to be a bit tricky, is discovering new composers. So, in the past I often ended up listening to the usual suspects (Debussy, Brahms, ...). I mean, of course there is nothing wrong with Debussy, but after some time I felt, as if I knew his work better, than he himself.
Fortunately there is a simple solution for my little issue: an article on Wikipedia.
Mikalojus Konstantinas Čiurlionis, for example, a Lithuanian painter, composer and writer, whose music is right now on my playlist.
So what I'm doing is simply picking a new artist from this endless list, head over to Spotify and look if I can find his/her works there – and usually I can.
I really love this little trick and I'm not only surprised of how many amazingly good piano composers there are (and were), but also of how much classical music Spotify has.