My Little Pony
Starting with the G1 series, each toy pony, unicorn or pegasus (winged horse) came in bright colors for example pink and blue, and a "cutie mark," or symbol on its rear end.  The symbol usually had something to do with its name and personality.  For example, the pegasus pony named Firefly had blue lightning bolts for her cutie mark.  Fireflies are also called lightning bugs.