The website Tat Designs has an extensive collection of printable tattoo designs. The designs on this site are grouped into categories such as Celtic designs, celebrity tattoos, angel and fairy tattoos and many more.
Tat Designs has 35 pages of grouped tattoo collections with each grouping leading to a new page of varying tattoo designs that fall within that design category. The site's collection of celebrity images are close-up photos showing the celebrity tattoos that could be used as bases for artists to design tattoos, but they are not actual templates exactly matching each celebrity's tattoo.
An additional resource is Free Tattoo Designs. Like Tat Designs, it provides many tattoo design images grouped by category. It also includes brief descriptions of the significance or meaning behind different types of tattoos.