Cast Mana Geyser by paying its mana cost
Holding priority, cast Reiterate with buyback by paying {4}{R}{R}, creating a copy of Mana Geyser and returning Reiterate to your hand.
Resolve the copy of Mana Geyser, adding at least six {R}.
Repeat from step 2.

Infinite magecraft triggers

Infinite red mana

Infinite storm count

Reiterate

Mana Geyser

Cast Mana Geyser by paying {3}{R}{R}, adding {R} for each tapped land your opponents control.
Cast Devastating Onslaught by paying {4}{R}, creating two token copies of Pinnacle Monk with haste.
When the Pinnacle Monk tokens enter, they trigger, returning Mana Geyser and Devastating Onslaught from your graveyard to your hand.
Repeat.

Infinite creature LTB

Infinite creature ETB

Infinite creature sacrifice triggers

Infinite death triggers

Infinite creature tokens with haste

Devastating Onslaught

Pinnacle Monk // Mystic Peak

Activate Soulfire Grand Master by paying {2}{U/R}{U/R}, causing you to put the next instant or sorcery card you cast from your hand this turn into your hand as it resolves.
Cast Mana Geyser by paying {3}{R}{R}, adding {R} for each tapped land opponents control and returning Mana Geyser to your hand.
Repeat.

Soulfire Grand Master

Cast Mana Geyser by paying {3}{R}{R}.
Holding priority, activate Rootha by paying {2} and returning it from the battlefield to your hand, copying Mana Geyser.
Resolve the copy of Mana Geyser, adding at least {R}{R}{R}.
Activate Sneak Attack by paying {R}, putting Rootha from your hand onto the battlefield.
Repeat from step 2.
If opponents control four or more tapped lands, this combo nets infinite red mana.

Rootha, Mercurial Artist

Sneak Attack

Cast Mana Geyser by paying {3}{R}{R}.
Extus triggers, returning Pinnacle Monk from your graveyard to your hand.
Resolve Mana Geyser, adding {R} for each tapped land your opponents control.
Cast Pinnacle Monk by paying its mana cost.
When Pinnacle Monk enters the battlefield, it triggers, returning Mana Geyser from your graveyard to your hand.
Activate Phyrexian Altar by sacrificing Pinnacle Monk, adding one mana of any color.
Repeat.

Infinite colored mana

Extus, Oriq Overlord // Awaken the Blood Avatar

Phyrexian Altar

Cast Mana Geyser by paying {3}{R}{R}, targeting an opponent with at least four cards in their hand.
Holding priority, activate Emiel by paying {3}, blinking Dualcaster Mage.
Dualcaster Mage enters the battlefield, copying Mana Geyser.
Resolve the copy of Mana Geyser, adding at least {R}{R}{R}{R}.
Repeat from step 2.

Infinite blinking

Dualcaster Mage

Emiel the Blessed

Cast Mana Geyser by paying {5}.
Holding priority, activate Mishchievous Quanar's morph ability by paying {3}, turning it face up.
Mischievous Quanar triggers, copying Mana Geyser.
Resolve the copy of Mana Geyser, adding {1} for each tapped land your opponents control.
Activate Mischievous Quanar's first ability by paying {5}, turning it face down.
Repeat from step 2.
If opponents control nine or more tapped lands, this combo nets infinite mana, which you can then use to activate Mischievous Quanar to get infinite copies of any other instant and/or sorcery spell(s) on the stack.

Infinite card draw

Infinite colorless mana

Infinite draw triggers

Infinite copies of instant and sorcery spells on the stack

Mischievous Quanar

Chromatic Orrery

Mycosynth Lattice

Cast Mana Geyser by paying {3}{R}{R}.
Holding priority, activate Emiel by paying {3}, blinking Naru Meha.
When Naru Meha enters the battlefield, it triggers, copying Mana Geyser.
Resolve the copy of Mana Geyser, adding at least {R}{R}{R}.
Repeat from step 2.
If opponents control four or more tapped lands, this combo nets infinite red mana.

Combos with "Mana Geyser"