The website Coloringcastle.com contains free downloadable coloring pages of hearts. Designs include single hearts, multiple hearts and hearts filled with words. Downloading from this website requires Adobe Acrobat.
Crayola.com offers free downloadable images of many shapes, including hearts. Elaborate heart designs for more advanced artists, including adults, can be found at Colorpagesformom.com. These images are also free downloads.
Coloring pages containing hearts can also be found in hard copy coloring books. Amazon.com offers several heart-themed coloring books for adults and children.
Coloring pages for anatomical hearts are available as free downloads from the American Heart Association at Heart.org. The coloring pages are part of their curriculum for elementary school teachers.