Silvanus's Invoker + Agatha of the Vile Cauldron + Gruul Turf

Silvanus's Invoker

Agatha of the Vile Cauldron

Gruul Turf

How it works

1. Activate Gruul Turf by tapping it, adding .
2. Activate Silvanus's Invoker by paying 1, untapping Gruul Turf and causing it to become an 8/8 Elemental with trample and haste in addition to its other types until end of turn.
3. Repeat.
4. Once you have infinite mana, you may tap and untap any other land(s) you control, and use the mana to activate Agatha of the Vile Cauldron's ability.

This clever loop relies on Agatha of the Vile Cauldron to slash the activation cost of Silvanus's Invoker down to just a single generic mana, making the Invoker's ability cheap enough to fuel itself entirely. By targeting the dual-mana-producing Gruul Turf with that untap effect, you can repeatedly generate more mana than the single pip required to activate the Invoker again, yielding infinite red and green mana along with infinite untaps of your lands. Once your mana is limitless, you can redirect those resources into Agatha of the Vile Cauldron's second ability to grant massive stats, trample, and haste to the rest of your board.