These recipes produce more of an item than they use, so feeding part of the output back in grows your supply.
Mechanical Mixer · From Create: High Pressure
+ Gravel, minecraft:lava
Its other inputs are renewable, so this loop gives an unlimited supply of Netherrack.
Mechanical Mixer · From Create: Synthetic Pressure
+ Gravel
Its other inputs are renewable, so this loop gives an unlimited supply of Netherrack.
Alaindustrial · Mutation duplicate · From Ala Industrial
Its other inputs are renewable, so this loop gives an unlimited supply of Nether Wart.
Create_cultivation · Cultivating · From Create: Cultivation Craft
Its other inputs are renewable, so this loop gives an unlimited supply of Nether Wart.
Mechanical_botany · Insolating · From Create: Mechanical Botany
+ minecraft:lava
Its other inputs are renewable, so this loop gives an unlimited supply of Nether Wart.
Minecraftcontentexpansion · Greenhouse · From MinecraftContentExpansion
Its other inputs are renewable, so this loop gives an unlimited supply of Nether Wart.
Mechanical Mixer · From Farwater: Create Mysticism
+ Cobblestone
Its other inputs are renewable, so this loop gives an unlimited supply of Blackstone.