Lichenthrope

If damage would be dealt to Lichenthrope, put that many -1/-1 counters on it instead.
At the beginning of your upkeep, remove a -1/-1 counter from Lichenthrope.

Melira, Sylvok Outcast

You can't get poison counters.
Creatures you control can't have -1/-1 counters put on them.
Creatures your opponents control lose infect.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Ashnod's Altar

Witherscale Wurm

Whenever Witherscale Wurm blocks or becomes blocked by a creature, that creature gains wither until end of turn. (It deals damage to creatures in the form of -1/-1 counters.)
Whenever Witherscale Wurm deals damage to an opponent, remove all -1/-1 counters from it.

Phyrexian Hydra

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
If damage would be dealt to Phyrexian Hydra, prevent that damage. Put a -1/-1 counter on Phyrexian Hydra for each 1 damage prevented this way.

Aerie Ouphes

Sacrifice Aerie Ouphes: It deals damage equal to its power to target creature with flying.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Woodfall Primus

Trample
When Woodfall Primus enters, destroy target noncreature permanent.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)