The cards have special backs with the Heroes of the Realm logo
While more thematically matching crossovers like Final Fantasy tend to get full-size sets, secret lair crossovers provide a space for something smaller and often a bit more light-hearted, like Hatsune Miku or Monty Python
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.) As long as Aetherwing is still an artifact, its ability will count Aetherwing itself
This one might be cheating because its from Dominaria United Commanders Legends Retold , but its my pick anyway
Enchantment Flash When Growing Dread enters, manifest dread
Additionally, each The Brothers' War Commander deck comes with a Collector Booster Sample Pack, which contains two cards: 1 Rare or mythic rare that can be a traditional foil, borderless, or extended-art card 1 Traditional foil uncommon retro artifact or retro schematic Your Collector Booster Sample Pack might contain a special version of one of the cards in your Commander deck or a card perfect to add to another Commander deck
