I listen to a lot of prog rock/metal and have a bunch of it downloaded. Because this genre is far less repetitive than most other genres and contains a lot of instrumental parts, it's great for me to listen to while working.

Octavarium by Dream Theater: https://www.youtube.com/playlist?list=OLAK5uy_kenWZqZjpo5SVB1Jqq5I_ymw9FXIpVOKQ

Close to the Edge by Yes: https://www.youtube.com/playlist?list=OLAK5uy_ktk8PtkXO8GdshsmXb6w0fhaCMMTsyFio

Pawn Hearts by Van Der Graaf Generator: https://www.youtube.com/playlist?list=OLAK5uy_kOWdkl7AREpLB5vkYkhbv94GHycru9xHY

Power Windows by Rush: https://www.youtube.com/playlist?list=PL6vwnon3sINreLuPXXORrhrCGUdRBsHzF