Skittering Precursor + Sword of the Meek + Nahiri's Resolve + Umbral Collar Zealot

Skittering Precursor

Sword of the Meek

Nahiri's Resolve

Umbral Collar Zealot

How it works

1. Activate Umbral Collar Zealot by sacrificing Sword of the Meek.
2. Skittering Precursor triggers, creating a 0/1 Eldrazi Spawn creature token.
3. When the Eldrazi Spawn enters the battlefield as a 1/1 due to Nahiri's Resolve, Sword of the Meek triggers, returning Sword of the Meek from your graveyard to the battlefield attached to the Eldrazi Spawn.
4. Resolve the Umbral Collar Zealot ability
5. Repeat.

This loop transforms your graveyard and sacrifice outlets into a self-sustaining engine by cleverly manipulating creature stats. Umbral Collar Zealot provides the initial sacrifice engine, feeding Sword of the Meek to the graveyard while letting you surveil through your deck. Because Nahiri's Resolve grants your creatures a passive +1/+0 buff, the Eldrazi Spawn token created by Skittering Precursor enters the battlefield as a 1/1 instead of a 0/1, which precisely meets the trigger condition needed to return Sword of the Meek straight from your graveyard to the battlefield.