Thraximundar

Haste
Whenever Thraximundar attacks, defending player sacrifices a creature.
Whenever a player sacrifices a creature, you may put a +1/+1 counter on Thraximundar.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Dreadhorde Invasion

At the beginning of your upkeep, you lose 1 life and amass Zombies 1. (Put a +1/+1 counter on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
Whenever a Zombie token you control with power 6 or greater attacks, it gains lifelink until end of turn.