These are just some highlights off the top of my head.
Function Falls by Buke and Gase. Home-brew electro-acoustic instruments with a penchant for digital pitch shifters, and a strong beautiful voice. All of their records are available on Bandcamp!
Koloss by Meshuggah. Still the masters of metal minimalism and/or Bootsy Collins-inspired funk bass. Hits: “Do Not Look Down”, “Marrow”, “Break Those Bones Whose Sinews Gave It Motion”, all the other tracks. Killer live show (with Decapitated and Baroness opening!).
Love This Giant by St. Vincent and David Byrne. Fresh arrangements and instrumentation, and great vocal dialogues. St. Vincent is as awesome a singer as she is a guitarist.
The Master soundtrack by Jonny Greenwood. Also this weird gem with Krzysztof Penderecki. Narrative and space. Try and buy these at the online store.
Non-2012 music that I especially loved in 2012:
Everything by Noveller (Sarah Lipstate). Guitar loops, noise, landscapes. You can get all her stuff on Bandcamp.
The out-of-print Japanese import of Living Colour’s Biscuits. So many awesome live tracks.
Carnival is Forever by Decapitated. A triumphant and inventive return from personal tragedy.