Standard Reveillark Combo deck
Reveillark Combo is a combo deck-control deck based around the infinite combo between Reveillark, Mirror Entity, and Body Double (explained below). The deck is often compared to Ravnica-Time Spiral Standard's Project X, in that the deck can win just fine without even assembling the combo. The deck plays similar to a normal Momentary Blink tempo deck, and often assembles the infinite combo passively.
How the Combo Works
In order to combo off, the player must have some combination of Reveillark, Body Double, Mirror Entity, and some comes-into-play two-power creature in play, in hand, or in the graveyard. For example, let's say the player has Reveillark and Riftwing Cloudskate in the graveyard, Mirror Entity in play, and Body Double in hand:
1. Player casts Body Double, targeting Reveillark.
2. Player activates Mirror Entity for 0 mana any number of times (generally, 20-30).
3. Player resolves the first Mirror Entity activation, turning all his creatures into 0/0s, killing them.
4. When Body Double (copying Reveillark) dies, his ability triggers, targeting Body Double (the same one that just died) and Riftwing Cloudskate.
5. Body Double (targeting Reveillark again) and Riftwing Cloudskate (targeting an opponent's permanent) come into play.
6. Player resolves second Mirror Entity activation (still 18-28 activations on the stack).
7. Repeat steps 4-6 until opponent has no permanents in play.
8. Resolve final Mirror Entity activation and return Body Double (targeting Reveillark again) and Mirror Entity to play.
9. By this point you can swing for a turn or two usually, and kill the opponent. Even if they do find a way to do something, you can just combo again since you still have all the pieces intact.
Sample decklist as piloted to 3rd place at Grand Prix Shizouka by Kenji Tsumura:
4 Adarkar Wastes
4 Nimbus Maze
4 Riftwing Cloudskate
3 Aven Riftwatcher
2 Body Double
2 Sower of Temptation
1 Mirror Entity
1 Venser, Shaper Savant
4 Mind Stone
2 Careful Consideration
2 Momentary Blink
4 Rune Snag
3 Wrath of God
3 Teferi's Moat
3 Remove Soul
2 Pact of Negation
2 Crovax, Ascendant Hero
1 Aven Riftwatcher
1 Sower of Temptation