Guile + Temporal Extortion + Aetherflux Reservoir

Guile

Temporal Extortion

Aetherflux Reservoir

How it works

1. Cast Temporal Extortion by paying .
2. Temporal Extortion and Aetherflux Reservoir trigger.
3. Resolve the Aetherflux Reservoir trigger, causing you to gain 1 life for each spell you've cast this turn.
4. Resolve the Temporal Extortion trigger, causing you to pay half your life total, rounded up, and then exile Temporal Extortion and cast it without paying its mana cost due to Guile.
5. Repeat.
6. Once you have infinite life, you may activate Aetherflux Reservoir infinite times to deal infinite damage to any target(s).