To coincide with the release of Legendary Duelists: Ancient Millennium, several cards have updated names or text that alter how they interact with some of the new cards.
Crystal Counter is now called Counter Gem. (It is not a “Crystal” card.)
Violet Crystal has a clause that states it is never treated as a “Crystal” card.
Hardened Armed Dragon has a clause that states it is never treated as an “Armed Dragon” card.
Ojamuscle has a clause that states it is always treated as an “Ojama” card.
Rainbow Dark Dragon has a clause that states it is always treated as an “Ultimate Crystal” card.
Rainbow Neos, Advanced Dark, and Rainbow Gravity have new text that replaces the original names of Rainbow Dragon and Rainbow Dark Dragon with the phrase “Ultimate Crystal cards”. So, for example, you may use Rainbow Overdragon as a material for Rainbow Neos. (At this time, they have not included Rainbow Path, most likely because Overdragon is a Fusion Monster and cannot interact with it anyway.)
Lastly, Rainbow Dragon has a physical reprint within the pack, with a clause that states it is always treated as an “Ultimate Crystal” card.
https://www.db.yugioh-card.com/yugiohdb/
