NFD (Nuggets For Diamonds) was a treasure hunt. One has to find gold nuggets renamed to 'Treasure Token' across the Shopping District and Hermit Land, then put them into the NFD machine in Hermit Land. For every nugget one puts in, there is a chance they will get nothing, a Diamond, or a Diamond Block.
It was created by MumboJumbo and Iskall85 in MumboJumbo's Season 6: Episode 126 after both MumboJumbo and Iskall85 admit defeat to a bet they both made to create a better villager trading hall than the other's.