Unknown Event

Legendary Creature — Dragon

Kevin can't be countered, devour 2
Flying, mountainwalk, rampage 2, bushido 2, trample over planeswalkers
Damage can't be prevented.
Players can't gain life.
Whenever Kevin deals combat damage to a player, gain control of target land that player controls. Untap it.

Kevin, Questing Dragon

The List

Creature — Phyrexian Horror

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

Glissa's Courier

Creature — Dwarf

Dwarven Grunt

Secret Lair Drop

Creature — Goat

Mountain Goat

Modern Masters

Creature — Giant Scout

Hillcomber Giant

Duel Decks: Ajani vs. Nicol Bolas

Creature — Cat

Canyon Wildcat

Zendikar

Creature — Kor Scout

Cliff Threader

Shards of Alara

Creature — Goblin Scout

Goblin Mountaineer

Tenth Edition

Creature — Badger Beast

Rock Badger

Ravnica: City of Guilds

Creature — Goblin Warrior

Goblin Spelunkers

Champions of Kamigawa

Creature — Ogre Warrior

Sokenzan Bruiser

Mercadian Masques

Creature — Insect

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
{R}: This creature gets +1/-1 until end of turn.

Cavern Crawler

Urza's Destiny

Creature — Goat Beast

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
{R}: This creature gets +1/+0 until end of turn.

Colos Yearling

Portal Three Kingdoms

Creature — Dog

Zodiac Dog

Zodiac Goat

Urza's Saga

Creature — Lizard

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
Echo {1}{R}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Vug Lizard

Chronicles

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
When you control a Dwarf, sacrifice this creature.

Goblins of the Flarg

Creature — Yeti

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
Protection from white

Mountain Yeti