I noticed a woman in a thumbhole tee the other day--she pushed up her sleeve a bit when she took her hand out of the cuff, & then you couldn't see the thumbhole at all. When she wanted to warm her hands up, she pulled the cuff back down.
Thumbholes tees make a cozy layer for winter. The tees below come in many colors & prints.
dELiA's thumbhole tees come in 12 colors. I like the stripes.