Toph, Greatest Earthbender + Power Depot + Crystalline Crawler + Yahenni, Undying Partisan + Doc Samson, Super Psychiatrist

Toph, Greatest Earthbender

Power Depot

Crystalline Crawler

Yahenni, Undying Partisan

Doc Samson, Super Psychiatrist

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 Doc Samson.
4. Activate Yahenni 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 Doc Samson.
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 Yahenni ability.
9. Activate Yahenni 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 loop transforms a modest earthbending casting investment into an unstoppable engine of endless mana and triggers, perfectly orchestrated by Doc Samson's ability to amplify every single counter that enters the battlefield. As Toph, Greatest Earthbender enters the fray, she earthbends Power Depot—which conveniently returns to the field via her trigger whenever Yahenni, Undying Partisan sacrifices it—while Doc Samson ensures that the land's modular counters grow exponentially larger with each iteration. Crystalline Crawler acts as our fantastic battery, converting those multiplied +1/+1 counters into the exact colored mana needed to recast Toph and keep the cycle spinning infinitely.