Fertilid

This creature enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from this creature: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Anara, Wolvid Familiar

During your turn, commanders you control have indestructible. (Effects that say "destroy" don't destroy them. A creature with indestructible can't be destroyed by damage.)
Partner (You can have two commanders if both have partner.)

Jolrael, Empress of Beasts

{2}{G}, {T}, Discard two cards: All lands target player controls become 3/3 creatures until end of turn. They're still lands.

Mark of Sakiko

Enchant creature
Enchanted creature has "Whenever this creature deals combat damage to a player, add that much {G}. Until end of turn, you don't lose this mana as steps and phases end."

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Keleth, Sunmane Familiar

Whenever a commander you control attacks, put a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)

Curse of Predation

Enchant player
Whenever a creature attacks enchanted player, put a +1/+1 counter on it.

Vitality Hunter

Lifelink
{X}{W}{W}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, put a lifelink counter on each of up to X target creatures.

Valor

First strike
As long as this card is in your graveyard and you control a Plains, creatures you control have first strike.

Cast Off

Destroy all non-Giant creatures. (Then exile this card. You may cast the creature later from exile.)

Realm-Cloaked Giant

Realm-Cloaked Giant // Cast Off

Dauntless Escort

Sacrifice this creature: Creatures you control gain indestructible until end of turn.

Ordeal of Nylea

Enchant creature
Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice this Aura.
When you sacrifice this Aura, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Shatter the Sky

Each player who controls a creature with power 4 or greater draws a card. Then destroy all creatures.

Loyal Guardian

Trample
Lieutenant — At the beginning of combat on your turn, if you control your commander, put a +1/+1 counter on each creature you control.

Kwende, Pride of Femeref

Double strike
Creatures you control with first strike have double strike.

Hamza, Guardian of Arashin

This spell costs {1} less to cast for each creature you control with a +1/+1 counter on it.
Creature spells you cast cost {1} less to cast for each creature you control with a +1/+1 counter on it.

Out of Time

When this enchantment enters, untap all creatures, then those creatures phase out until this enchantment leaves the battlefield. Put a time counter on this enchantment for each creature that phased out this way.
Vanishing (At the beginning of your upkeep, remove a time counter from this enchantment. When the last is removed, sacrifice it.)

Ainok Bond-Kin

Outlast {1}{W} ({1}{W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has first strike.

Outland Colossus

Renown 6 (When this creature deals combat damage to a player, if it isn't renowned, put six +1/+1 counters on it and it becomes renowned.)
This creature can't be blocked by more than one creature.

Kodama of the West Tree

Reach
Modified creatures you control have trample. (Equipment, Auras you control, and counters are modifications.)
Whenever a modified creature you control deals combat damage to a player, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Grateful Apparition

Flying
Whenever this creature deals combat damage to a player or planeswalker, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Good-Fortune Unicorn

Whenever another creature you control enters, put a +1/+1 counter on that creature.

Constable of the Realm

Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
Whenever one or more +1/+1 counters are put on this creature, exile up to one other target nonland permanent until this creature leaves the battlefield.

Orzhov Advokist

At the beginning of your upkeep, each player may put two +1/+1 counters on a creature they control. If a player does, creatures that player controls can't attack you or planeswalkers you control until your next turn.