Cast Timestream Navigator by paying {1}{U}.
Timestream Navigator enters the battlefield, triggering Inalla, causing you to pay {1} to create a token copy of Timestream Navigator with haste.
If you do not have the city's blessing, Timestream Navigator triggers, giving you the city's blessing for the rest of the game.
Activate Riptide Laboratory by paying {1}{U} and tapping it, returning the nontoken Timestream Navigator to your hand from the battlefield.
Activate the token Timestream Navigator by paying {2}{U}{U}, tapping it, and putting it on the bottom of your library, causing you to take an extra turn after this one.
Repeat each turn.

Infinite turns

Timestream Navigator

Riptide Laboratory

Inalla, Archmage Ritualist

Cast Timestream Navigator by paying {1}{U}.
If you don't have the city's blessing and control ten or more permanents, Timestream Navigator gives you the city's blessing.
When Timestream Navigator enters the battlefield, Molten Echoes triggers, creating a token copy of Timestream Navigator with haste.
If you don't have the city's blessing, the Timestream Navigator token gives you the city's blessing.
Activate Riptide Laboratory's second ability by paying {1}{U} and tapping it, returning the nontoken Timestream Navigator to your hand from the battlefield.
Activate the Timestream Navigator token by paying {2}{U}{U}, tapping it and putting it on the bottom of your library from the battlefield, causing you to take an extra turn after this one.
Repeat each turn.

Molten Echoes

Cast Timestream Navigator by paying {1}{U}.
Reflections of Littjara triggers, copying the Timestream Navigator spell.
Resolve the copy of the Timestream Navigator spell.
If you don't have the city's blessing and control ten or more permanents, the Timestream Navigator token gives you the city's blessing.
Resolve the original Timestream Navigator spell.
If you don't have the city's blessing, Timestream Navigator gives you the city's blessing.
Activate Riptide Laboratory's second ability by paying {1}{U} and tapping it, returning the nontoken Timestream Navigator to your hand from the battlefield.
During your next turn, repeat steps 1 through 7 one additional time.
Activate the oldest Timestream Navigator token by paying {2}{U}{U}, tapping it and putting it on the bottom of your library from the battlefield, causing you to take an extra turn after this one.
Repeat from step 8 each turn.

Reflections of Littjara

Cast Timestream Navigator by paying {1}{U}.
Archmage of Echoes triggers, copying the Timestream Navigator spell.
Resolve both Timestream Navigator spells.
If you don't have the city's blessing, either the Timestream Navigator token or the nontoken Timestream Navigator gives you the city's blessing.
During your next turn, activate Riptide Laboratory's second ability by paying {1}{U} and tapping it, returning the nontoken Timestream Navigator to your hand from the battlefield.
Activate the ability of the Timestream Navigator token by paying {2}{U}{U}, tapping it and putting on the bottom of your library, causing you to take an extra turn after that one.
Repeat.

Archmage of Echoes

Cast Turnabout by paying {2}{U}{U}, targeting any land you control.
Holding priority, cast Dualcaster Mage by paying {1}{R}{R}.
Dualcaster Mage enters the battlefield, copying Turnabout.
Holding priority, activate Riptide Laboratory by paying {1}{U} and tapping it, returning Dualcaster Mage to your hand.
Resolve the Turnabout copy, untapping all lands you control.
Repeat from step 2.

Infinite colored mana

Infinite ETB

Infinite LTB

Infinite storm count

Dualcaster Mage

Turnabout

Cast Timestream Navigator by paying {1}{U}.
If you don't have the city's blessing and control ten or more permanents, Timestream Navigator gives you the city's blessing.
When Timestream Navigator enters the battlefield, Flameshadow Conjuring triggers, causing you to pay {R} to create a token copy of Timestream Navigator with haste.
If you don't have the city's blessing, the Timestream Navigator token gives you the city's blessing.
Activate Crystal Shard by paying {3} or {U} and tapping it, returning the nontoken Timestream Navigator to your hand from the battlefield.
Activate the Timestream Navigator token by paying {2}{U}{U}, tapping it and putting it on the bottom of your library from the battlefield, causing you to take an extra turn after this one.
Repeat each turn.

Flameshadow Conjuring

During an opponent turn, after their upkeep, cast Reset for {U}{U}.
In response, cast Dualcaster Mage at instant speed for {1}{R}{R}.
Resolve Dualcaster Mage, and target Reset with his triggered ETB ability to copy Reset.
Resolve the Reset copy untapping your lands including Riptide Laboratory.
In response to the original Reset still on the stack, activate Riptide Laboratory's activated ability for {1}{U} and tap targeting Dualcaster Mage.
Resolve Riptide Laboratory's activated ability returning Dualcaster Mage to your hand.
Tap all lands other than Riptide Laboratory.
Repeat.

Infinite colorless mana

Reset

Cast TImestream Navigator by paying {1}{U}, plus an additional {2} for its offspring cost.
If you control ten or more permanents and don't have the city's blessing, Timestream Navigator gives you the city's blessing.
When Timestream Navigator enters the battlefield, it triggers, creating a token copy of it that is 1/1.
If you control ten or more permanents and don't have the city's blessing, the Timestream Navigator token gives you the city's blessing.
Activate Riptide Laboratory by paying {1}{U} and tapping it, returning the nontoken Timestream Navigator from the battlefield to your hand.
During your next turn, repeat steps 1 through 5 one additional time.
Activate the oldest Timestream Navigator token by paying {2}{U}{U}, tapping it and putting it from the battlefield onto the bottom of your library, causing you to take an extra turn after this one.
Repeat from step 8.

Combos with "Riptide Laboratory"