Druid's Familiar

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Druid's Familiar is paired with another creature, each of those creatures gets +2/+2.

Grizzly Fate

Create two 2/2 green Bear creature tokens.
Threshold — Create four 2/2 green Bear creature tokens instead if seven or more cards are in your graveyard.
Flashback {5}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Bearscape

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

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Ayula's Influence

Discard a land card: Create a 2/2 green Bear creature token.

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.)

Owlbear Cub

Mama's Coming — Whenever Owlbear Cub attacks a player who controls eight or more lands, look at the top eight cards of your library. You may put a creature card from among them onto the battlefield tapped and attacking that player. Put the rest on the bottom of your library in a random order.

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.

Runeclaw Bear

Kami of Whispered Hopes

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.
{T}: Add X mana of any one color, where X is Kami of Whispered Hopes's power.

Grizzly Bears

Ashcoat Bear

Flash (You may cast this spell any time you could cast an instant.)

Hunt the Weak

Put a +1/+1 counter on target creature you control. Then that creature fights target creature you don't control. (Each deals damage equal to its power to the other.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Mother Bear

{3}{G}{G}, Exile Mother Bear from your graveyard: Create two 2/2 green Bear creature tokens. Activate only as a sorcery.

Rampant Growth

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

Ulvenwald Bear

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