Scholar of New Horizons + Intruder Alarm + Lesser Masticore + Ashnod's Altar
Scholar of New Horizons
Intruder Alarm
Lesser Masticore
Ashnod's Altar
Infinite colorless manaInfinite death triggersInfinite creature ETBInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creaturesPut all Plains cards from your libary into your hand
How it works
Activate Ashnod's Altar by sacrificing Lesser Masticore, adding CC.
Lesser Masticore dies, triggering its persist ability, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Lesser Masticore enters the battlefield, triggering Intruder Alarm, untapping all creatures.
Activate Scholar of New Horizons by tapping it and removing the -1/-1 counter from Lesser Masticore, causing you to search your library for a Plains card and either put it onto the battlefield or put it into your hand.