Plains

Priests of Norn

Vigilance
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Benevolent Bodyguard

Sacrifice Benevolent Bodyguard: Target creature you control gains protection from the color of your choice until end of turn.

Lost Leonin

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Corpse Cur

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Corpse Cur enters, you may return target creature card with infect from your graveyard to your hand.

Ichorclaw Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Ichorclaw Myr becomes blocked, it gets +2/+2 until end of turn.