Will, Scion of Peace + Phyrexian Altar + Sedgemoor Witch + Mystic Speculation

Will, Scion of Peace

Phyrexian Altar

Sedgemoor Witch

Mystic Speculation

How it works

1. Activate Will by tapping it, reducing the cost of all white and/or blue spells you cast this turn by at least 2.
2. Cast Mystic Speculation with buyback by paying due to Will's ability.
3. Sedgemoor Witch triggers, creating a 1/1 Pest creature token.
4. Resolve Mystic Speculation, causing you to scry 3 and return it to your hand.
5. Activate Phyrexian Altar by sacrificing the Pest, adding .
6. When the Pest dies, it triggers, causing you to gain 1 life.
7. Repeat from step 2.

This loop relies on Will, Scion of Peace drastically discounting your spells based on life gained, which allows you to cast Mystic Speculation over and over for just a single blue mana thanks to its buyback cost. As you repeatedly cast Mystic Speculation, Sedgemoor Witch watches every single spell via magecraft to constantly churn out Pest tokens. You then feed those very tokens into Phyrexian Altar to generate the exact blue mana needed to sustain the loop while simultaneously triggering the Pests' built-in death ability to gain life. That constant lifegain pumps Will, Scion of Peace's cost reduction even higher, locking down an infinite storm and scry engine.