I’ve been compiling a list of focus inducing songs on Deezer.
My method is to vet a random playlist by listening to it during an intense coding session. If I can make it through without getting distracted I add it to my focus playlist.
I have a subsequent vetting process where - if at any point when listening to a song on my focus playlist - a song grabs my attention I’ll remove it.
It’s grown to over 75 hours of music at this point. I can listen to it for days on shuffle without hearing anything familiar which helps keep it in the background.