Putting a creature in tapped and attacking with lesser power than Shadowfax from your hand is some serious mana advantage essentially granting super-haste. It doesnt even bounce back to hand
Vehicles require you to tap a commander to crew them, to make them into creatures, giving you a safe way to constantly tap King Macar so you can untap it later
Pumpkin Carriage Pumpkin Carriage has basically no statline with 0 attack points and 800 defense (in the anime), but it allows Cinderella to bypass all opposing monsters and attack directly, allowing her to transfer her Glass Slippers onto opposing monsters pretty quickly
Additional cards (previously in other expansions)
return it to the hand, and if you do, the activated effect becomes "Your opponent randomly discards 1 card"
Sky Striker Ace - Kagari might just be the last card you see