Three more versions of Tam Lin:
Perilous Gard by Elizabeth Marie Pope, Houghton Mifflin, 1974 (This is in a lot of fantasy and folklore bibliographies, but I don't know id it won any awards)

Tam Lin by Joan D. Vinge. This is a short story in the anthology Imaginary Lands, edited by Robin McKinley 1986, Greenwillow Books

Tam Lin by Susan Cooper, Margaret K. McElderry Books, 1991