The Ancient Treasures are a series of cards used by Tenzen Yanagi, as well as Yusei Fudo briefly, in the Yu-Gi-Oh! 5D's anime. According to the anime, it is possible that they are illegal, but currently that is not a problem. This set focuses on Rock-Type monsters with 0 ATK to do its bidding, and nearly all of the cards have a negative effect (paying LP, discarding, etc.). These cards work well with "Curse Reflection Doll" and "Triangle O" to deflect the negative effects, however.
These cards are based on ancient objects from various locales around the world. Its theme would later be reused in the form of the "Chronomaly" archetype by Trey in Yu-Gi-Oh! ZEXAL.