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 - $14.20
Lightly Played - $11.40
Moderately Played - $9.90
Heavily Played - $8.50
Damaged - $7.10
Near Mint Spanish - $14.20
Lightly Played Spanish - $11.40
Moderately Played Spanish - $9.90
Heavily Played Spanish - $8.50
Damaged Spanish - $7.10