Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Mayhem Devil

Whenever a player sacrifices a permanent, this creature deals 1 damage to any target.

Ashnod's Altar

Fling

As an additional cost to cast this spell, sacrifice a creature.
Fling deals damage equal to the sacrificed creature's power to any target.

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on this creature.

Szarel, Genesis Shepherd

Flying
You may play lands from your graveyard.
Whenever you sacrifice another nontoken permanent during your turn, put a number of +1/+1 counters equal to Szarel's power on up to one other target creature.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.