I think Fall/Autumn would be nice, considering that it's almost that time of year.
Other Ideas:
Black & White
Brown
Black Background
White Background
Brights
Pastels
Christmas
Solids
Animals (sort of I-Spy-ish, but as I understand it, the I-Spy hostess isn't able to host any swaps at the moment due to health issues.
Hope she's feeling better soon! <3 )
Primary Colors
Stripes
Civil War Repro
Sewing Notions/Themes
Anything Goes
Rainbow
1930's Repro