Cocoa pebbles are gluten-free and an excellent source of vitamin D. So you can feel good about serving a cereal that kids love to eat. Introduced in 1971, cocoa pebbles cereal with its delicious chocolatey taste has been a family favorite for over 40 years. Only pebbles has the fun of fred flintstone, barney rubble, and the rest of the flintstones gang. Post pebbles is a deliciously fun and wholesome part of a complete breakfast.