The fastest, most hostile Dredge build, Manaless Dredge poses a unique threat because it casts no spells directly from hand and has no lands.
Manaless Dredge is one of the few decks that always wants to be on the draw so that you can discard on your first turn. As stated above, you never need to cast a spell since your graveyard is effectively your hand. You can attrition out with Zombie tokens, Ichorid, and Nether Shadow for a late game grind or kill quickly with the combo. The combo kill in the deck is Balustrade Spy, which mills your whole deck and Flayer of the Hatebound. The Balustrade Spy will immediately mill your deck and give you access to every spell possible. It's effectively drawing your whole deck. Flayer with Dread Return and other threats will kill your opponent on the spot by reanimating Golgari Grave-Troll. This list will kill on turn two with extreme consistency. If undisturbed, Manaless Dredge will always kill.
Out of the sideboard, there are cards that can adjust the deck one way or another. Contagion and Sickening Shoal are mainly to deal with Deathrite Shaman and Scavenging Ooze. Mindbreak Trap and Leyline of Sanctity are for combo match ups. Finally, there is an extra Cabal Therapy if you deem that extra disruption is needed. Generally, the sideboard is not used for most match ups since it dilutes your decks overall power level.
As expected, graveyard hate is the absolute end of the deck. This list cannot beat any resolved graveyard hate, especially Leyline of the Void or Rest in Peace. Chancellor of the Annex can delay some of the hate until you can initiate the kill, but this list cannot beat a turn zero Leyline of the Void.
Hostile, consistent, and a load of fun, Manaless Dredge is a deck for the bold and fun-seeking Legacy players. If you are unafraid of hate and want a powerful, fun list to pilot, give this deck a try.