Blasting Station

{T}, Sacrifice a creature: This artifact deals 1 damage to any target.
Whenever a creature enters, you may untap this artifact.

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of this creature instead.

Life and Limb

All Forests and all Saprolings are 1/1 green Saproling creatures and Forest lands in addition to their other types. (They're affected by summoning sickness.)

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.