You guys are probably more familiar with this than me, but I haven't seen it mentioned so far:
Thom Yorke and Modeselektor Shipwreck/Dull Hull EP (loved this stuff)
Thom Yorke, Four Tet and Burial - Ego and Mirror (fantastic)
Thom Yorke and MF Doom - Retarded Fren (a must for anyone who loves either/or)
Thom Yorke and PJ Harvey - This mess we're in
Thom and Andy Yorke collabing on a song, loved that too
On a Friday obvious for any Radiohead fan of course
Drugstore Ft Thom Yorke (wasn't huge on this)
UNKLE Ft Thom Yorke - Rabbit in your headlights (absolutely love)
Thom had a role in what is now Lunatic Calm. The two bands were called Headless Chickens and Flickernoise I believe, he played guitar and contributed backing vox. I don't think he had much of a role in Flickernoise.
The fashion show bits and pieces he did (they were okay, wasn't too huge on most of them if I'm honest)
Feeling pulled apart by horses and Hollow Earth seem to get little mention by most, love those two.