Owlbear

Trample
Keen Senses — When Owlbear enters the battlefield, draw a card.

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters the battlefield, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Dragon-Scarred Bear

Formidable — {1}{G}: Regenerate Dragon-Scarred Bear. Activate only if creatures you control have total power 8 or greater.

Ayula, Queen Among Bears

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

Mother Bear

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

Werebear

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

Striped Bears

When Striped Bears enters the battlefield, draw a card.

Goreclaw, Terror of Qal Sisma

Creature spells you cast with power 4 or greater cost {2} less to cast.
Whenever Goreclaw, Terror of Qal Sisma attacks, each creature you control with power 4 or greater gets +1/+1 and gains trample until end of turn.

Ulvenwald Bear

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

Druid's Familiar

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. 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.

Pale Bears

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