Unlike Dylan, who arguably left his best song unreleased, it seems clear that Radiohead doesn't sit on anything really great. Virtually ever song that was recorded during OK Computer and then re-recorded at a later date substantially improved. In Rainbows Nude is a million times better than the OKC version. True Love Waits got a lot better. National Anthem and Glass House got better.
Honestly, I am a bit surprised that such a great album didn't have more great outtakes. Most of them are outtakes for a reason. The only exception I can think of is Lift. But maybe I missed a few gems in the leak.