Activate Rofellos by tapping it, adding at least {G}{G}{G}.
Activate Rofellos by paying {3} and untapping it, giving it +2/+2 until end of turn.
Repeat.

Infinite green mana

Infinitely large creature until end of turn

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Umbral Mantle

Rofellos, Llanowar Emissary

Activate Marvin using Rofellos's ability by tapping it, adding at least {G}{G}.
Activate Marvin using Farmstead Gleaner's ability by paying {2} and untapping it, putting a +1/+1 counter on Marvin.
Repeat.

Infinite +1/+1 counters on a creature

Marvin, Murderous Mimic

Farmstead Gleaner

Activate Rofellos by tapping it, adding at least {G}{G}{G}.
Activate Voltaic Construct by paying {2}, untapping Rofellos.
Repeat

Infinite colored mana

Infinite untap of artifact creatures you control

Voltaic Construct

Mycosynth Lattice

Activate Rofellos by tapping it, adding at least {G}{G}{G}.
Activate Scryb Ranger by returning it from the battlefield to your hand, untapping Rofellos.
Cast Scryb Ranger by paying {1}{G}.
Repeat.

Infinite LTB

Infinite ETB

Infinite storm count

Infinite landfall triggers

Ashaya, Soul of the Wild

Scryb Ranger

Activate Rofellos by tapping it, adding at least {G}{G}{G}{G}{G}.
Cast Hyrax Tower Scout by paying {2}{G}.
When Hyrax Tower Scout enters the battlefield, it triggers, untapping Rofellos.
Activate Kogla by paying {1}{G}, returning Hyrax Tower Scout from the battlefield to your hand.
Repeat.

Kogla, the Titan Ape

Hyrax Tower Scout

Activate Rofellos by tapping it, adding at least {G}{G}{G}.
Activate Magus of the Candelabra by paying {2} and tapping it, untapping it and Rofellos.
Repeat.

Infinite mana lands you control can produce

Infinite untap of nontoken creatures you control

Infinite mana nontoken creatures you control can produce

Infinite untap of lands you control

Magus of the Candelabra

Activate Marvin using Rofellos's ability by tapping it, adding at least {G}{G}.
Activate Marvin using Pili-Pala's ability by paying {2} and untapping it, adding one mana of any color.
Repeat.

Pili-Pala

Activate Rofellos by tapping it, adding at least {G}{G}{G}.
Activate Candelabra of Tawnos by paying {2} and tapping it, untapping it and Rofellos.
Repeat.

Card that Animates an Artifact

Candelabra of Tawnos

Activate Rofellos by tapping it, adding at least {G}{G}{G}{G}{G}
Activate Chrome Dome by paying {5}, creating a token copy of Sewer-veillance Cam.
When the Sewer-veillance Cam token enters, it triggers, untapping Rofellos.
Repeat.

Infinite copies of artifacts you control with haste

Infinite creature tokens with haste

Infinite death triggers

Infinite sacrifice triggers

Chrome Dome

Sewer-veillance Cam

Activate Experiment Kraj using Rofellos's ability by tapping it, adding at least {G}{G}{G}.
Activate Experiment Kraj using Gilder Bairn's ability by paying {2}{G/U} and untapping it, doubling each counter on target permanent.
Repeat.

Infinite proliferate

Experiment Kraj

Gilder Bairn

Activate Rofellos by tapping it, adding at least {G}{G}.
Activate Arcanis's first ability by tapping it, causing you to draw three cards.
Tolarian Kraken triggers three times. Resolve the first two triggers, causing you to pay {2} to untap Arcanis and Rofellos.
Resolve the last Tolarian Kraken trigger, choosing not to pay.
Repeat.

Infinite card draw

Infinite draw triggers

Near-infinite untap of creatures you control

Near-infinite mana creatures you control can produce

Arcanis the Omnipotent

Tolarian Kraken

Activate Rofellos by tapping it, adding at least {G}{G}.
Cast Wirewood Symbiote by paying {G}.
Activate Mirror Entity by paying {1}, giving creatures you control all creature types and base power and toughness 1/1 until end of turn.
Activate Wirewood Symbiote by returning it from the battlefield to your hand, untapping Rofellos.
Repeat.

Infinitely large creatures you control until end of turn

Wirewood Symbiote

Mirror Entity

Activate Rofellos by tapping it, adding at least {G}{G}{G}{G}.
Activate Mind Over Matter by discarding a card, untapping Rofellos.
Activate Tasigur by paying {2}{G/U}{G/U}, causing you to mill two cards and return a nonland card from your graveyard to your hand.
Repeat.

Infinite self-mill

Infinite self-discard triggers

Infinite mana permanents you control can produce

Tasigur, the Golden Fang

Mind Over Matter

Activate Rex using Rofellos's ability by tapping it, adding at least {G}{G}.
Activate Rex using Pili-Pala's ability by paying {2} and untapping it, adding one mana of any color.
Repeat.

Rex, Cyber-Hound

Activate Rofellos by tapping it, adding at least {G}{G}{G}.
Activate Emiel by paying {3}, blinking Derevi.
When Derevi enters the battlefield, it triggers, untapping Rofellos.
Repeat.

Combos with "Rofellos, Llanowar Emissary"