Zombie Master

Other Zombie creatures have swampwalk. (They can't be blocked as long as defending player controls a Swamp.)
Other Zombies have "{B}: Regenerate this permanent."

Ghoulraiser

When Ghoulraiser enters, return a Zombie card at random from your graveyard to your hand.

Accursed Marauder

When Accursed Marauder enters, each player sacrifices a nontoken creature of their choice.

Gempalm Polluter

Cycling {B}{B} ({B}{B}, Discard this card: Draw a card.)
When you cycle Gempalm Polluter, you may have target player lose life equal to the number of Zombies on the battlefield.