Biovisionary + Finale of Promise + Croaking Counterpart

Biovisionary

Finale of Promise

Croaking Counterpart

How it works

1. Cast Finale of Promise by paying 10, causing you to cast Croaking Counterpart from your graveyard without paying its mana cost and copying it twice, with all spells targeting Biovisionary.
2. Resolve all Croaking Counterparts, creating three token copies of Biovisionary that are 1/1 Frogs.
3. At the beginning of your end step, each Biovisionary you control triggers.
4. Resolve the first trigger, causing you to win the game.

This explosive win relies on dumping massive mana into Finale of Promise to reach its threshold where X is 10 or greater, allowing you to cast Croaking Counterpart from your graveyard and automatically copy it twice. The original spell and its two copies all target your lone Biovisionary, rapidly populating the battlefield with three fresh token copies of it. Because Biovisionary's own static check triggers at the beginning of the end step and simply asks if you control four or more creatures with that exact name, resolving even the first of those triggers seals your victory right then and there.