Activate Fertilid by paying {1}{G} and removing a +1/+1 counter from it, causing you to search your library for a basic land card and put it on the battlefield untapped due to Spelunking.
When the basic land enters, Lotus Cobra and Obuun trigger.
Resolve the Lotus Cobra trigger, adding {G}.
Resolve the Obuun trigger, putting a +1/+1 counter on Fertilid.
Activate the basic land by tapping it, adding {1}.
Repeat.

Near-infinite landfall triggers

Put all basic land cards from your library onto the battlefield tapped

Fertilid

Lotus Cobra

Obuun, Mul Daya Ancestor

Spelunking

Activate Fertilid by paying {1}{G} and removing a +1/+1 counter from it, causing you to search your library for a basic land card and put it on the battlefield untapped due to Amulet of Vigor.
When the basic land enters, Amulet of Vigor, Lotus Cobra and Obuun trigger.
Resolve the Amulet of Vigor trigger, untapping the basic land.
Resolve the Lotus Cobra trigger, adding {G}.
Resolve the Obuun trigger, putting a +1/+1 counter on Fertilid.
Activate the basic land by tapping it, adding {1}.
Repeat.

Amulet of Vigor

Activate Xavier Sal by tapping it and removing a counter from a permanent you control, creating a token copy of the Forest Dryad token.
When the Forest Dryad enters the battlefield, Intruder Alarm and Obuun trigger.
Resolve the Obuun trigger, putting a counter on it.
Resolve the Intruder Alarm trigger, untapping all creatures.
Repeat.

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