More watercolor flowers. The stamps are by Hero Arts. They have a whole series of these stamps.
Another method of coloring on the stamps is watercolor crayons. Depending on your brand of crayons, you can mist the stamp and color directly on the rubber or color on the rubber without misting. You will have to mist again after coloring.
Felt tip markers can be used too. Color on the rubber and "huff" on it with your warm moist breath. After stamping you can "huff" again or mist.
I have even carefully inked my stamps with dye based ink pads, stamped, misted and stamped again. Ink with the lightest color first to prevent the dark color (in this case the green) from bleeding onto you light ink pad.
STAMPER HINT - you stamped in a dark ink, forgot to clean or did not clean your stamp well. When you use the stamp again on a light ink pad you can see that dark image on the ink pad. GASP!!! the pad is ruined!!! or is it?? Nope it's not ruined. With a little bit of effort you can clean your light ink pad. Using a paper towel, repeatedly dab the dark ink on the pad. Use clean parts of the paper towel with each dab and eventually you will have all that dark ink lifted from your pad. You may have to reink, but that is far less expensive than buying a new ink pad.