Of course, the biggest upside of Zirda, the Dawnwaker is that its cost reduction applies to all permanents (see: the Basalt Monolith / Grim Monolith combos for Commander), and some artifact-based decks come very close to accidentally meeting Zirda, the Dawnwaker's companion restriction (for example, Modern Urza decks often only have Uro, Titan of Nature's Wrath as a permanent without an activated ability), so the unique wording on Zirda might open up new possibilities, compared to Biomancer's Familiar and Training Grounds, that will take time to explore
destroy 1 Synchro Monster your opponent controls, and if you do, inflict damage to your opponent equal to its original ATK
So I would say, play 'em while you got 'em
Hyper Librarian Limited Monster/Xyz Cards Beatrice, Lady Of The Eternal Daigusto Emeral Limited Spell Cards Called By The Grave Card Destruction Card Of Demise Chain Strike Change of Heart Chaos Space Chicken Game Divine Wind Of Mist Valley Dragonic Diagram Final Countdown Foolish Burial Gateway Of The Six Gold Sarcophagus Harpies Feather Duster Infernity Launcher Instant Fusion Into The Void Magical Mid-Breaker Field Monster Gate Monster Reborn One Day Of Peace One For One Reasoning Reinforcement Of The Army Sekkas Light Set Rotation Sky Striker Mecha Hornet Drones Slash Draw Snatch Steal Terraforming Limited Trap Cards Anti-Spell Fragrance Gozen Match Magical Explosion Naturia Sacred Tree Rivalry of Warlords There Can Be Only One Time Seal Semi-Limited Yu-Gi-Oh
Some newer Dinosaur support cards are cross-support with the Dragon, Sea Serpent, and Wyrm Types, likely in reference to how all four Types contain the word "dragon" in their Japanese names ("terror dragon" in this one's case, mirroring how the English name means "terrible lizard" in Greek)
