The list contains a lot of game soundtracks from games that I have played a lot when I was younger. Game soundtracks in mostgames are built to be enjoyed while not distracting the player, so they are perfect for work. The soundtracks gives me that nostalgic feeling and makes the work much more fun. My productivity increases a lot when I play these songs.
I really like the soundtracks from Oblivion, Skyrim, Ocarina Of Time and Age of Empires. They songs are very calm and brings back good memories. Starcraft and Fallout are also pretty good to listen to. You can find all the work music / game soundtracks right below.