There’s an awesome mix over at Music vs. Misery. I would especially recommend Song #9 as The Good Natured covering Sufjan is incredible–reminiscent of First Aid Kit covering Fleet Foxes.
I was surprised to find I already had some of the songs I thought I didn’t know in my iTunes (#s 6 and 26 for example). Need to go on a “what haven’t I listened to” quest sometime soon.