Fertilid by paying ({1} magic symbol) ({G} magic symbol) 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
Horizon Explorer.
When the basic land enters,
Tireless Provisioner and
Felidar Retreat trigger.
Resolve the
Tireless Provisioner trigger, creating a Treasure token.
Activate the Treasure by tapping and sacrificing it, adding ({G} magic symbol) .
Resolve the
Felidar Retreat trigger, putting a +1/+1 counter on
Fertilid.
Activate the basic land by tapping it, adding ({1} magic symbol) .
Repeat.
Results
Near-infinite landfall triggers.
Put all basic land cards from your library onto the battlefield tapped.