Murder

Zombies are first and foremost: black creatures. Mono black is the original zombie tribal colours, and later received multiple great cards in Dimir colors.

With mono black zombie tribals are fully combat focused decks with resource advantage from abusing the graveyard. With looting effects, discard and creatures dying the graveyard is zombie decks most valuable resource after the zombies on the battlefield.

Aristocrat decks are a combination of sacrifice effects, reanimating and value creation. Wincons revolve around multiple triggers, either from dying, ETB or cast triggers.

Reanimate decks brings back creatures from the graveyard straight to the battlefield. The reanimated creatures are often expensive to cast, like demons, and are complete haymakers compared to the reanimation costs.

Lifegain is one of the the most popular themes in EDH. Multiple triggers to gain life and value received from the lifegain triggers are really fun to follow as a player. Often lifegain is combined with another theme, +1/+1 counters or creature tokens, as pure lifegain is often not powerful enough to win the game.

Vampire tribal is second most popular mono black tribal. Eternal vampire have a multitude of different commanders available and different game plans, too. One vampire tribal can focus on full combat with lord effects, other focusing on life gain and life loss and third can focus on stealing other players creatures.