This is a few of the darling House Mouse Stamps. If not familiar you can search the company by putting in search bar, House Mouse Rubber Stamps;
Mine were done in colored pencil and gamasol which provides almost a painted smooth look. You have to play around with them and practice. Place your color light first around the edges, and with blending stub dip tip in gamasol. Then gently circular motion bring out the edge color to the center.
the colors are vivid and delightful. I am an avid user of watercolors, in most everything to do with art/coloring. I have since discovered the ease and mobile (take them with me to crops)