Bur-Yur, The Goblin King

Bur-Yur, the Goblin King cannot attack alone.
Other Goblins you control get +1/+1 and mountainwalk
Whenever another Goblin you control deals combat damage to an opponent, that player may let you
create a Treasure token. If they don't, that player sacrifices a noncreature permanent.
{5}{t}, sacrifice a Goblin: Reveal the top 5 cards of your library and put all Goblins from
among them onto the battlefield