Toph, Greatest Earthbender + Power Depot + Crystalline Crawler + Bloodflow Connoisseur + Shang-Chi, Martial Mentor

Toph, Greatest Earthbender

Power Depot

Crystalline Crawler

Bloodflow Connoisseur

Shang-Chi, Martial Mentor

How it works

1. Play Power Depot, which will enter with a +1/+1 counter on it due to its modular ability
2. Cast Toph either from your hand or from the command zone by paying 2 plus commander tax if applicable.
3. When Toph enters, it triggers, earthbending Power Depot and putting a number of +1/+1 counters on Power Depot equal to the mana spent to cast Toph, increased by Shang-Chi.
4. Activate Bloodflow Connoisseur by sacrificing Power Depot.
5. When Power Depot dies, its modular ability and Toph trigger.
6. Resolve the modular trigger, putting the +1/+1 counters that were on Power Depot onto Crystalline Crawler, increased by Shang-Chi.
7. Resolve the Toph trigger, returning Power Depot from your graveyard to the battlefield tapped. Power Depot will enter with a +1/+1 counter on it due to its modular ability
8. Resolve the Bloodflow Connoisseur ability.
9. Activate Bloodflow Connoisseur by sacrificing Toph. Choose to return Toph from your graveyard to the command zone.
10. Activate Crystalline Crawler by removing a +1/+1 counter from it, adding R/G.
11. Repeat step 10 until you have enough mana to cast Toph.
12. Repeat from step 2.

This clever loop turns the mechanical synergy of earthbending and modular into a perpetual engine for infinite mana and counters. Power Depot acts as our recurring sacrifice target, bringing itself back via Toph, Greatest Earthbender whenever it hits the graveyard. While Shang-Chi, Martial Mentor supercharges every counter that gets distributed throughout the chain, Crystalline Crawler acts as our mana battery by converting those growing stockpiles into the exact colors we need. Finally, Bloodflow Connoisseur provides the reliable sacrifice outlet to keep the cycle spinning, ensuring that Toph and her trusty land can return to the battlefield over and over again.