Basking Broodscale + Renata, Called to the Hunt + Yuna, Grand Summoner

Basking Broodscale

Renata, Called to the Hunt

Yuna, Grand Summoner

How it works

1. Cast Basking Broodscale by paying 1, which enters with a +1/+1 counter on it due to Renata.
2. Basking Broodscale triggers, creating a 0/1 Eldrazi Spawn creature token that enters with a +1/+1 counter on it due to Renata.
3. Activate the Eldrazi Spawn by sacrificing it, adding C.
4. When the Eldrazi Spawn dies, Yuna triggers, putting a +1/+1 counter on Basking Broodscale.
5. Repeat from step 2.

This loop relies on Renata, Called to the Hunt as a foundational engine, ensuring that both Basking Broodscale and the tokens it generates always enter the battlefield with at least one +1/+1 counter. That built-in counter placement triggers Basking Broodscale's ability to spawn a 0/1 Eldrazi Spawn, which you can immediately sacrifice for colorless mana. When that token dies with its counter, Yuna, Grand Summoner steps in with her trigger to place a fresh +1/+1 counter right back onto Basking Broodscale. This continuous cycle not only feeds itself indefinitely to generate infinite mana and sacrifice triggers, but can also be supercharged if Yuna, Grand Summoner's tap ability was used earlier to help cast your creatures with even more bonus counters.