Agatha of the Vile Cauldron + Cryptolith Rite + Devoted Druid + Barrenton Medic

Agatha of the Vile Cauldron

Cryptolith Rite

Devoted Druid

Barrenton Medic

How it works

1. Activate Agatha of the Vile Cauldron by paying , giving all other creatures you control +1/+1, trample and haste until end of turn.
2. Activate Devoted Druid and Barrenton Medic by tapping them, adding .
3. Activate Devoted Druid and Barrenton Medic's second abilities by putting a -1/-1 counter on them, untapping them.
4. Repeat.

This clever loop turns Devoted Druid and Barrenton Medic into an infinite mana and untap engine by leveraging the passive cost reduction of Agatha of the Vile Cauldron. Normally, putting a -1/-1 counter on these creatures to untap them would quickly run out of steam, but Agatha of the Vile Cauldron discounts those activated abilities while Cryptolith Rite quietly turns every tapping action into raw mana of any color. Once you have your infinite engine humming, pour that mana back into Agatha of the Vile Cauldron's pump ability to hand out infinite power, toughness, trample, and haste to your entire team for a decisive alpha strike.