Essence Warden

Whenever another creature enters, you gain 1 life.

Emmara, Soul of the Accord

Whenever Emmara, Soul of the Accord becomes tapped, create a 1/1 white Soldier creature token with lifelink.

Bess, Soul Nourisher

Whenever one or more other creatures you control with base power and toughness 1/1 enter, put a +1/+1 counter on Bess, Soul Nourisher.
Whenever Bess attacks, each other creature you control with base power and toughness 1/1 gets +X/+X until end of turn, where X is the number of +1/+1 counters on Bess.