Doom's Time Platform + Rift Elemental + Time Warp

Doom's Time Platform

Rift Elemental

Time Warp

How it works

1. Cast Time Warp by paying its mana cost, causing you to take an extra turn after this one.
2. Declare any creature as an attacker. When you do, Doom's Time Platform triggers, exiling Time Warp from your graveyard with two time counters on it.
3. Move to your next turn. At the beginning of your upkeep, Time Warp's suspend ability triggers, removing a time counter from it.
4. Activate Rift Elemental by paying 1 and removing a time counter from Time Warp.
5. Time Warp's suspend ability triggers, causing you to cast it without paying its mana cost.
6. Resolve Time Warp, causing you to take an extra turn after this one.
7. Repeat from step 2.

This elegant loop bends time to your will by continuously recycling an extra turn spell right out of the graveyard. Every time you declare an attack, Doom's Time Platform catches your recently cast Time Warp and tucks it away into exile with a pair of time counters, granting it suspend so it's primed to re-enter the fray. Normally you'd have to wait patiently for your upkeeps to tick those counters away one by one, but Rift Elemental lets you actively accelerate the clock by shaving off the final counter on demand. Once that counter is gone, Time Warp springs back out of exile for free, granting you yet another turn to attack, trigger Doom's Time Platform all over again, and loop infinitely.