As proliferate can be used to add counters to anything that already has counters on it, you can garner favor with opponents by growing some of their creatures or planeswalkers
This is mostly because Skysovereign has developed into an odd Pioneer staple thanks to Karn, the Great Creator tutoring it from sideboards in Mono-Green Devotion and Greasefang, Okiba Boss decks using it as a secondary payoff alongside Parhelion II
The last new mechanic is celebration
That being said, more Storm is always better, and sadly it can be difficult to generate lethal Storm counts
[c]Flying Crane Technique[/c] is the kind of card that turns a game around in one turn and often wins it in that turn too
(2/4/2023) To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents