You can find Rainbow Dragon from the Collector's Tin (Secret Rare) and from Tactical Evolution packs (also Secret Rare). You can find the Crystal Beasts in Force of the Breaker and Jesse Anderson Duelist Packs (Sapphire Pegasus can also be found in a tin, Secret Rare) If you play OCG, you can find ALL the Crystal Beasts and Rainbow Dragon in the Johan Anderson Duelist Pack (make sure it's an OCG pack, the TCG one lacks Pegasus and Rainbow Dragon).