Dredge
Dredge is the keyword attributed to the Golgari in the Ravnica block. It is a mechanic of recursive nature, where the owner of a card in a graveyard with said ability can return the card to their hand by choosing to skip his or her draw and put a number of cards from his or her library into his or her graveyard. The actual number of cards that must be put into a graveyard is written on each card with Dredge. Dredge only appears on green and/or black cards.
From the ()
Ichorid
One of the most popular uses of Dredge is to use it to quickly fill your graveyard. A famous deck based on Ichorid originated from this concept. Such decks work best with cards with high Dredge values, such as Golgari Grave-Troll and Stinkweed Imp. Another style of decks using this mechanic that debuted in the tournament scene are Life from the Loam decks, which use the card to gain card advantage by continuously recycling lands with cycling, as well as other utility lands like Wasteland and Cephalid Coliseum.
The Extended Dredge deck was a common deck archetype built around this mechanic.