Anafenza, Kin-Tree Spirit

Whenever another nontoken creature you control enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Aven Tactician

Flying
When Aven Tactician enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Light of the Legion

Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
When Light of the Legion dies, put a +1/+1 counter on each white creature you control.

Dragonscale General

At the beginning of your end step, bolster X, where X is the number of tapped creatures you control. (Choose a creature with the least toughness among creatures you control and put X +1/+1 counters on it.)

Sunhome Stalwart

First strike (This creature deals combat damage before creatures without first strike.)
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Elite Scaleguard

When Elite Scaleguard enters, bolster 2. (Choose a creature with the least toughness among creatures you control and put two +1/+1 counters on it.)
Whenever a creature you control with a +1/+1 counter on it attacks, tap target creature defending player controls.

Abzan Skycaptain

Flying
When Abzan Skycaptain dies, bolster 2. (Choose a creature with the least toughness among creatures you control and put two +1/+1 counters on it.)

Honor's Reward

You gain 4 life. Bolster 2. (Choose a creature with the least toughness among creatures you control and put two +1/+1 counters on it.)

Abzan Advantage

Target player sacrifices an enchantment of their choice. Bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters tapped unless you control three or more other Plains.
When Idyllic Grange enters untapped, put a +1/+1 counter on target creature you control.

Dromoka Captain

First strike
Whenever Dromoka Captain attacks, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Echoes of the Kin Tree

{2}{W}: Bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Sandcrafter Mage

When Sandcrafter Mage enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Parhelion Patrol

Flying
Vigilance (Attacking doesn't cause this creature to tap.)
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Enduring Victory

Destroy target attacking or blocking creature. Bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Gleam of Authority

Enchant creature
Enchanted creature gets +1/+1 for each +1/+1 counter on other creatures you control.
Enchanted creature has vigilance and "{W}, {T}: Bolster 1." (To bolster 1, choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Blade Instructor

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Scale Blessing

Bolster 1, then put a +1/+1 counter on each creature you control with a +1/+1 counter on it. (To bolster 1, choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)