These recipes produce more of an item than they use, so feeding part of the output back in grows your supply.
Create_cultivation · Cultivating · From Create: Cultivation Craft
Its other inputs are renewable, so this loop gives an unlimited supply of Pink Petals.
Theurgy · Replication · From Theurgy
Its other inputs are renewable, so this loop gives an unlimited supply of Bone Meal.
Cyclic · Solidifier · From Cyclic
Its other inputs are renewable, so this loop gives an unlimited supply of Slimeball.