Non Sequitur 
Sells artistic rubber stamps for collages, cards and other works of art. Rubber stamp images come in sheets of unmounted rubber (plates).
http://www.nonsequiturstamps.com/New Stamp on the Block
Transparent acrylic art stamps for rubber stampers and scrapbooking.
http://www.newstampontheblock.com/
Nature's Blessings
Offers antiquarian stamps, classically elegant to the quirky and fun. Also offers Calligraphy and Art Lettering, and stamps for holidays and special occasions.
http://www.naturesblessings.com/
