Pale Bears

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

Werebear

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

Balduvian Bears

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 this creature is paired with another creature, each of those creatures gets +2/+2.

Forest Bear

Casal, Pathbreaker Owlbear

Vigilance, trample
When this creature transforms into Casal, Pathbreaker Owlbear, other legendary creatures you control get +2/+2 and gain trample until end of turn.
At the beginning of your upkeep, transform Casal.

Casal, Lurkwood Pathfinder

Vigilance
When Casal enters, search your library for a Forest card, put it onto the battlefield tapped, then shuffle.
Whenever Casal attacks, you may pay {1}{G}. If you do, transform her.

Casal, Lurkwood Pathfinder // Casal, Pathbreaker Owlbear

Runeclaw Bear

Duskana, the Rage Mother

When Duskana enters, draw a card for each creature you control with base power and toughness 2/2.
Whenever a creature you control with base power and toughness 2/2 attacks, it gets +3/+3 until end of turn.

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.

River Bear

Striped Bears

Ulvenwald Bear

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

Bear Cub

Mother Bear

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

Kudo, King Among Bears

Other creatures have base power and toughness 2/2 and are Bears in addition to their other types.

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.)

Grizzly Bears

Ashcoat Bear

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

Lumra, Bellow of the Woods

Vigilance, reach
Lumra's power and toughness are each equal to the number of lands you control.
When Lumra enters, mill four cards. Then return all land cards from your graveyard to the battlefield tapped.