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 - $20.900
Lightly Played - $16.800
Moderately Played - $14.700
Heavily Played - $12.600
Damaged - $10.500
Near Mint Spanish - $20.900
Lightly Played Spanish - $16.800
Moderately Played Spanish - $14.700
Heavily Played Spanish - $12.600
Damaged Spanish - $10.500