Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)
"Hup, two, three, four,
Dunno how to count no more."
Near Mint - $23.25
Lightly Played - $18.25
Moderately Played - $16.25
Heavily Played - $14.25
Damaged - $11.25
Near Mint Spanish - $23.25
Lightly Played Spanish - $18.25
Moderately Played Spanish - $16.25
Heavily Played Spanish - $14.25
Damaged Spanish - $11.25