Leonardo, Sewer Samurai + Solemnity + Bloodflow Connoisseur + Ornithopter

Leonardo, Sewer Samurai

Solemnity

Bloodflow Connoisseur

Ornithopter

How it works

1. Activate Bloodflow Connoisseur by sacrificing Ornithopter.
2. Cast Ornithopter from your graveyard by paying 0. It will not enter with a finality counter on it due to Solemnity.
3. Repeat.

This clever loop centers around the synergy between Leonardo, Sewer Samurai and Solemnity, which together bypass the usual graveyard restrictions of the samurai. While Leonardo, Sewer Samurai normally brands creatures cast from your graveyard with a finality counter, Solemnity's static ability flat-out prevents any counters from being placed on creatures. This allows you to cast Ornithopter for zero mana over and over again from your graveyard. Meanwhile, Bloodflow Connoisseur provides the necessary sacrifice outlet to send the tiny flyer right back to the graveyard, growing itself with infinite +1/+1 counters in the process.