Cast Reins of Power by paying {2}{U}{U}.
Holding priority, activate all mana-producing creatures you control by tapping them, adding at least {U}{U}.
Activate Echo Mage by paying {U}{U} and tapping it, copying Reins of Power twice.
Resolve the first copy of Reins of Power, untapping all creatures you and target opponent control, and exchanging control of those creatures.
Resolve the second copy of Reins of Power, untapping all creatures you and target opponent control, and exchanging control of those creatures, causing you to regain control of all the creatures you originally controlled.
Repeat from step 2.
If creatures you control can tap to produce at least {1}{U}{U}, this combo nets infinite mana.

Infinite magecraft triggers

Infinite mana creatures you control can produce

Infinite mana creatures you control can produce for target opponent

Infinite untap of creatures you control

Reins of Power

Echo Mage

Cast Cackling Counterpart by paying its mana cost, targeting Biovisionary.
Holding priority, activate Echo Mage by tapping it, copying Cackling Counterpart twice, with both copies targeting Biovisionary.
Resolve all Cackling Counterpart spells, creating three token copies of Biovisionary.
At the beginning of your end step, each Biovisionary triggers. Resolve the first trigger, causing you to win the game.

Win the game

Biovisionary

Cackling Counterpart

Cast High Tide by paying {U}.
Cast Twitch by paying {2}{U}, targeting Echo Mage.
Holding priority, activate an Island by tapping it, adding {U}{U}.
Activate Echo Mage by paying {U}{U} and tapping it, copying Twitch twice, with the copies targeting an Island and Echo Mage.
Resolve both Twitch copies, untapping Echo Mage and an Island and causing you to draw two cards.
Repeat from step 3.

Infinite card draw

Infinite draw triggers

Near-infinite magecraft triggers

Twitch

High Tide

Cast Doppelgang by paying {6}{G}{U}, targeting Pestermite and a mana-producing permanent.
Holding priority, activate Echo Mage by paying {U}{U} and tapping it, copying Doppelgang, targeting Pestermite and a mana-producing permanent.
Resolve the copy of Doppelgang, creating two copies of Pestermite and the mana-producing permanent.
When the Pestermite tokens enter, they trigger, untapping Echo Mage and any other applicable permanent.
Holding priority, activate the two mana-producing permanent tokens by tapping them, adding at least {U}{U}.
Repeat from step 2.

Combos with "Echo Mage"