Critters/Animals
Chickens
Chickens are friendly animals that drop 0-1 Feathers and 0-1 Raw Chicken when they are killed.
Cows
Cows are friendly animals that drops 0-3 raw beef when they are killed.
Sheeps
Sheep are friendly animals that drops 1 wool when they are killed.
Pigs
Pigs are friendly animals that drops 1-3 pork chops when they are killed.
Mobs
Creepers
Creepers explode when you go near them. If you can kill them, you might get gunpowder.
Skeletons
Skeletons can get killed either you kill them, or the sun burns them. You can get bones or arrows if you kill them, but you will not get it 100% every time.
Zombies
Zombies can get killed either you kill them, or the sun burns them. You can get feathers if you kill them, but you will not get it 100% every time.
Spiders
Spiders don't get burned by the sun. They give you string when you kill them.