Cyclonic Rift is the most popular, but can often leave players feeling salty, particularly if you cast it on their end step
Cloudstone Curio An incredibly interesting idea, but likely far too slow for Modern
Smothering Tithe is probably the most obvious, but there are tons of other options too
In Nayas case, this means cards that benefit from lots of creatures or a bunch of extra mana
More recently, cards like Oko, Thief of Crowns and Once Upon A Time have been spotlit in discussions on pushing card mechanics a little too far, with both cards needing bans across several formats to keep the game healthy
So many of these cards are great, but I really dig these Clattering Skeletons by Phil Stone