I stumbled upon this website called Music For Programmers, a website with curated music for programming. On the About-page I found this rather interesting text:

Through years of trial and error – skipping around internet radio stations, playing our entire music collections on shuffle, or just hammering single albums on repeat, we have found that the most effective music to aid prolonged periods of intense concentration tends to have a mixture of the following qualities:

Drones
Noise
Fuzz
Field recordings
Vagueness (Hypnagogia)
Textures without rhythm
Minor complex chords
Early music (Baroque, lute, harpsichord)
Very few drums or vocals
Synth arpeggios
Awesome
Walls of reverb

Music possessing these qualities can often provide just the right amount of interest to occupy the parts of your brain that would otherwise be left free to wander and lead to distraction during your work.

A programmer works his way through complexity to find solutions and structure for complex things. I can see the parallels between this complexity and the structured music that is shared on Music For Programmers. Its has unpredictability at its music core. Going into all sorts of directions. Not limiting itself to predictable rhythms, song structures, lyrics telling a story. The brain needs to go different places when thinking, when programming. Allowing itself to make new and creative connections.

It is music for the brain, but as contradictory as it might sound, it makes you not think about the music. It makes you think about something else instead.

Might work for non-programmers too. Stop listening, start focussing and start thinking.