Vigor + Hanabi Blast + Crystalline Crawler + Conspiracy Theorist + Vorinclex, Monstrous Raider

Vigor

Hanabi Blast

Crystalline Crawler

Conspiracy Theorist

Vorinclex, Monstrous Raider

How it works

1. Cast Hanabi Blast by paying 1, targeting Crystalline Crawler.
2. Resolve Hanabi Blast, putting four +1/+1 counters on Crystalline Crawler due to Vigor's first ability, and then returning Hanabi Blast to your hand and discarding a card at random.
3. Conspiracy Theorist's second ability triggers, allowing you to exile the discarded card from your graveyard if it was a nonland card and cast it from exile this turn.
4. Activate Crystalline Crawler's first ability three times by removing three +1/+1 counters from it, adding 1.
5. Cast Hanabi Blast either from your hand or from exile by paying 1.
6. Repeat from step 2.
7. Once you have infinite colored mana, you may instead target any other creature and/or player with Hanabi Blast.

This clever engine uses Vigor to turn the damage from Hanabi Blast into a massive influx of +1/+1 counters on Crystalline Crawler, whose counters can then be removed for mana to recast the spell. The sheer mathematics of this loop are supercharged by Vorinclex, Monstrous Raider, which doubles the counters Vigor places and ensures the Crawler grows exponentially. Meanwhile, Conspiracy Theorist cleanly catches the card discarded at random by Hanabi Blast's drawback, exiling it so you can simply replay it from exile to keep the loop going indefinitely.