2. Teferi, Hero of Dominaria - Dominaria

Control is as much a problem as the illusion of control

Why is it good?

Teferi, Hero of Dominaria is the best planeswalker in the current meta. His ability to untap two lands not only makes him essentially a 3cc planeswalker, but it works in perfect synergy for control decks to have open mana to have access to counterspells and removals. In a pinch, he even has the ability to tuck a non-land permanent into the deck and buy time to find solutions for it. The last ability all but finishes the game by exiling everything on the board of the opponent.

What Decks is it used?

Teferi is singlehandedly the reason why Jeskai control is such a good build in the current meta. Jeskai has access to counterspells, draws, and removals, and Teferi has good synergy with all those elements. A late-game Teferi drop is the win-con of most Jeskai decks, and for good reason. You can also see Teferi make appearances in Esper Control decks, and UW midrange decks.