Toph, Greatest Earthbender + Power Depot + Crystalline Crawler + Woe Strider + Shang-Chi, Martial Mentor

Toph, Greatest Earthbender

Power Depot

Crystalline Crawler

Woe Strider

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 Woe Strider 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 Woe Strider ability.
9. Activate Woe Strider 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 intricate loop turns the synergy between Toph, Greatest Earthbender and Power Depot into a self-sustaining mana and counter engine. As Power Depot is repeatedly sacrificed to Woe Strider and returned to the battlefield via Toph's earthbend trigger, Crystalline Crawler acts as the battery, peeling off +1/+1 counters to generate the exact colored mana needed to recast your commander. Meanwhile, Shang-Chi, Martial Mentor supercharges the entire operation by doubling every single counter that lands on your permanents, rapidly escalating your resources until you can loop the process indefinitely.