Hello Fresco is a small brand from Austin, Texas with a clean, modern sense of graphic design.
Concrete Hermit is a UK art and design gallery which also curates and produces its own line of artist-designed t-shirts. The designs cover a variety of styles and artists.
Jessalin Beutler is a minimalist artist whose geometric designs translate perfectly to t-shirts. All of her clothing is organic and hand-painted with non-toxic ink.
Romibello is a German brand with tons of great, cleverly designed graphic tees. The Spreadshirt system allows you to pick what color American Apparel shirt you want.