Overwhelming Stampede

Until end of turn, creatures you control gain trample and get +X/+X, where X is the greatest power among creatures you control.

Tawnos, the Toymaker

Whenever you cast a Beast or Bird creature spell, you may copy it, except the copy is an artifact in addition to its other types. (The copy becomes a token.)

Radagast, Wizard of Wilds

Ward {1}
Beasts and Birds you control have ward {1}.
Whenever you cast a spell with mana value 5 or greater, choose one —
• Create a 3/3 green Beast creature token.
• Create a 2/2 blue Bird creature token with flying.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Elder Gargaroth

Vigilance, reach, trample
Whenever Elder Gargaroth attacks or blocks, choose one —
• Create a 3/3 green Beast creature token.
• You gain 3 life.
• Draw a card.

Rampaging Baloths

Trample
Landfall — Whenever a land you control enters, you may create a 4/4 green Beast creature token.

Sol Ring

Birds of Paradise

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

Craterhoof Behemoth

Haste
When Craterhoof Behemoth enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

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.