Kids love turtles! They're gentle, but tough, slow but persistent. Aesop's "Tortoise and the Hare" teaches young children that slow and steady wins the race, the power of determination, and to never understimate others. Teenage Mutant Ninja Turtles shout Turtle power! Other famous turtles include: Franklin, Crush from Finding Nemo, Koopa from Mario Bros., and Yertle by Dr. Seuss.
One of the best Turtle resources is Tucker Turtle. Tucker is a Turtle who teaches ways to calm and social skills instruction. Check out Tucker resources.