Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Forest

Bear Cub

Ulvenwald Bear

Morbid — When this creature enters, if a creature died this turn, put two +1/+1 counters on target creature.

Golden Bear

Bearscape

{1}{G}, Exile two cards from your graveyard: Create a 2/2 green Bear creature token.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Yeva, Nature's Herald

Flash (You may cast this spell any time you could cast an instant.)
You may cast green creature spells as though they had flash.

Runeclaw Bear

Balduvian Bears

Wilson, Refined Grizzly

This spell can't be countered.
Vigilance, reach, trample
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Choose a Background (You can have a Background as a second commander.)

Emerald Medallion

Green spells you cast cost {1} less to cast.

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Mosswort Bridge

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {G}.
{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Friendly Teddy

When this creature dies, each player draws a card.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Ruxa, Patient Professor

Whenever Ruxa enters or attacks, return target creature card with no abilities from your graveyard to your hand.
Creatures you control with no abilities get +1/+1.
For each creature you control with no abilities, you may have that creature assign its combat damage as though it weren't blocked.

River Bear

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)

Evercoat Ursine

Trample
Hideaway 3, hideaway 3 (When this creature enters, look at the top three cards of your library, exile one face down, then put the rest on the bottom in a random order. Then do it again.)
Whenever this creature deals combat damage to a player, if there are cards exiled with it, you may play one of them without paying its mana cost.

Ayula, Queen Among Bears

Whenever another Bear you control enters, choose one —
• Put two +1/+1 counters on target Bear.
• Target Bear you control fights target creature you don't control.

Caller of the Claw

Flash
When this creature enters, create a 2/2 green Bear creature token for each nontoken creature put into your graveyard from the battlefield this turn.

Sol Ring

Grizzly Bears

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sylvan Anthem

Green creatures you control get +1/+1.
Whenever a green creature you control enters, scry 1.

Werebear

{T}: Add {G}.
Threshold — This creature gets +3/+3 as long as there are seven or more cards in your graveyard.