Any repeatable proliferate effect synergizes well with everything from planeswalkers to poison counters and beyond
The card selection and advantage it provides shines in lots of formats, from Legacy to Cube to EDH
Just generally buffing things to survive is also decent, and at 1 mana its a decent turn 1 drop to buff things up as an enchantment deck builds, if youre going tall to deal damage, or you have proliferate, or you can double counters
I think this has been great for the childhood whimsy of the franchise, though not necessarily great for the quality of the games
Tarkir: Dragonstorm has powerful cards, and is new enough to be Standard-legal, but old enough to dip down from it's peak price
The most broken spell in Magic history, that's what