Astor, Bearer Of Blades is a low casting cost on its own, making it so you can start taking advantage of its ability early on in the game and start swinging your Vehicles in your damage as soon as possible
Having a consistent way to not only create a second combat phase but also untap all the creatures you control for a measly four mana is a phenomenal pairing, especially when used as a Commander to bring her back into the fight after being targetted
This is a hugely playable card not just because of its Shift cost, but the potential to cast it for free and return discarded characters to your deck at the same time
Although the number of cards featuring this mechanic is small, we thought it was crucial to do this element justice, and the modal kicker execution was by far the cleanest
Mindspring Merfolk is good in a Merfolk deck, and Gas Guzzler in Edgar, sure