3 The Moxes This one is technically a cheat, because there are five different Moxes, but they all do the same thing so it's easier to consolidate them into one entry
The Clone Saga The most significant part of The Clone Saga is that its clone chapter creates a nonlegendary copy, which is significant in Commander because you get a second copy of your commander
Mind Twist has quite a narrow window in which to end the game
There are even great support pieces at lower rarities, too, like Zack Fair and Weapons Vendor
This is sad news for bargain hunters, but the good news is that you'll still pick up plenty of free packs by playing
While I dont consider it a powerhouse (at least compared to several cards on this list), at a purely competitive standpoint, it still offers a good counter for energy spammers or decks centered around energy-hungry active cards while youre setting up your Gardevoir EX