The List

Creature — Dog

Haste
When this creature enters, it deals 4 damage to you.

Lava Hounds

Tenth Edition

Creature — Lizard

Menace (This creature can't be blocked except by two or more creatures.)

Viashino Runner

Eighth Edition

Enchantment — Aura

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has first strike. (It deals combat damage before creatures without first strike.)

Reflexes

Beatdown Box Set

Creature — Rhino

Crash of Rhinos

Friday Night Magic 2000

Creature — Snake

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{G}: Regenerate this creature.

River Boa

Classic Sixth Edition

Python

Creature — Boar

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Warthog

Urza's Saga

Creature — Ape Warrior

Gorilla Warrior

World Championship Decks 1997

Creature — Elephant

When this creature enters, sacrifice it unless you sacrifice a Forest.

Rogue Elephant

Weatherlight

Creature — Wolf

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When this creature enters, draw a card.

Arctic Wolves

Fifth Edition

Creature — Aurochs

Trample
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Aurochs

Creature — Wolverine

Rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)

Wolverine Pack

Visions

When this creature enters, sacrifice it unless you return two Forests you control to their owner's hand.

Bull Elephant

Creature — Hippo

Whenever this creature attacks and isn't blocked, you may have defending player activate a mana ability of each land they control and lose all unspent mana. If you do, this creature assigns no combat damage this turn and at the beginning of your next main phase this turn, you add an amount of {C} equal to the amount of mana that player lost this way.