In Minecraft, mobs are the creatures.
Some are good, some are bad, and some are even deadly.
Here I'll show you all the mobs in Minecraft.

(Note: While normally you can only tame Wolves in Minecraft, our server uses a modification called Pet Creeper that lets us turn most mobs into pets by right clicking them with a certain item in hand. That's why it says "Pet Food")

Good Mobs

Pig:
Screen_shot_2011-07-22_at_9.15.45_AM.pngexternal image PigFace.png

Status:Good, Approachable
Drops:0-2 Raw Porkchops, 0-2 Cooked Porkchops (If in contact with lava or fire)
Produce:(None)
Pet Food:Raw Porkchop

Sheep:
Screen_shot_2011-07-22_at_9.17.26_AM.pngexternal image SheepFace.png

Status:Good, Approachable
Drops:1 Wool
Produce:2-4 Wools (When sheared)
Pet Food:Sugar Cane

Cow:
Screen_shot_2011-07-22_at_9.17.46_AM.pngexternal image CowFace.png

Status:Good, Approachable
Drops:0-2 Leathers, 1-3 Raw Beefs, 1-3 Steaks (If in contact with lava or fire)
Produce:Milk (Right-click with bucket)
Pet Food:Unknown

Chicken:
Screen_shot_2011-07-22_at_9.18.17_AM.pngexternal image ChickenFace.png

Status:Good, Approachable
Drops:0-2 Feathers, 1 Raw Chicken, 1 Cooked Chicken (If in contact with lava or fire)
Produce: Eggs(Randomly)
Pet Food:Seeds

Squid:
Screen_shot_2011-07-22_at_9.18.32_AM.pngexternal image Squidface.png

Status:Good, Approachable
Drops:0-3 Ink Sacs
Produce:(None)
Pet Food:Unknown

Mooshroom:
external image 150px-Mooshroom.pngexternal image MooshroomFace.png

Status:Good, Approachable
Drops:0-2 Leathers, 1-3 Raw Beefs, 1-3 Steaks (If in contact with lava or fire)
Produce:Mushroom Stew (Right-click with bowl), Milk (Right-click with bucket), 2-5 Red Mushrooms (When sheared)
Pet Food:Unknown

Villagers:
external image Villagers.gifexternal image Villagerhead.png
Status:Good, Approachable
Drops:(None)
Produce:(None)
Pet Food: Unknown

Neutral Mobs:

Wolves:
Screen_shot_2011-07-22_at_9.27.54_AM.pngexternal image WolfFace.png

Status:Good Unless Hurt, Approachable
Drops:(None)
Produce:(None)
Pet Food:Bones

Zombie Pigmen:
Screen_shot_2011-07-22_at_9.27.38_AM.pngexternal image ZombiePigmanFace.png

Status:Good Unless Hurt, Approachable
Drops:0-3 Cooked Porkchops
Pet Food:Unknown

Spiders:
Screen_shot_2011-07-26_at_1.02.34_PM.pngexternal image SpiderFace.png

Status:Good Unless Night, Approachable Unless Night
Drops:0-2 Strings, 0-1 Spider Eye
Produce:(None)
Pet Food:Unknown

Endermen:
external image 100px-Enderman_normal.pngexternal image EndermanFace.png
Status:Good Unless Looked At, Approachable
Drops:0-1 Ender Pearl
Produce:(None)
Pet Food:Unknown

Bad Mobs:

Zombies:
Screen_shot_2011-07-26_at_1.02.56_PM.pngexternal image ZombieFace.png

Status:Bad, Unapproachable
Drops:0-2 Rotten Fleshs
Produce:(None)
Pet Food:Flint

Skeletons:
Screen_shot_2011-07-26_at_1.03.10_PM.pngexternal image SkeletonFace.png

Status:Bad, Unapproachable
Drops:0-2 Bones, 0-2 Arrows
Produce:(None)
Pet Food:Unknown

Creepers:
Screen_shot_2011-07-26_at_1.03.26_PM.pngexternal image CreeperFace.png

Status:Bad, Unapproachable
Drops:0-2 Gunpowders
Produce:Music Discs (When killed by a Skeleton)
Pet Food:Unknown

Slimes:
Screen_shot_2011-07-26_at_1.03.50_PM.pngexternal image SlimeFace.png

Status:Bad, Approachable
Drops:0-2 Slimeballs
Produce:(None)
Pet Food:Unknown

Spider Jockeys:
Screen_shot_2011-07-26_at_1.04.07_PM.pngexternal image Spider%2BSkeletonFace.png

Status:Bad, Unnaproachable
Drops:0-2 Strings, 0-2 Bones, 0-2 Arrows, 0-1 Spider Eye
Produce:(None)
Pet Food:Unknown

Ghasts:
Screen_shot_2011-07-26_at_1.04.33_PM.pngexternal image GhastFace.png

Status:Bad, Unapproachable
Drops:0-2 Gunpowders, 0-1 Ghast Tear
Produce:(None)
Pet Food:Unknown

Cave Spiders:
external image 150px-Blue_Spider_2.pngexternal image CaveSpiderFace.png
Status:Bad, Unapproachable
Drops:0-2 Strings, 0-1 Spider Eye
Produce:(None)
Pet Food:Unknown

Blazes:
external image 150px-Blaze.pngexternal image Blaze_Face.png
Status:Bad, Unnaproachable
Drops:0-1 Blaze Rod
Produce:(None)
Pet Food:Unknown

Silverfish:
external image 150px-Silverfish.pngexternal image SilverfishFace.png
Status:Bad, Unnaproachable
Drops:(None)
Produce:(None)
Pet Food:Unknown

Magma Cubes:
external image 150px-Magma_Cube.pngexternal image Magma_Cube_Face.png
Status:Bad, Approachable
Drops:(None)
Produce:(None)
Pet Food:Unknown

Utility Mobs:

Snow Golems:
external image 150px-Snow_Golem.pngexternal image Snowgolemhead.png
Status:Good, Approachable
Drops:10-15 Snowballs
Produce:(None)
Pet Food:Unknown

Boss Mobs:

Enderdragons:
external image 250px-Enderdragon.pngexternal image Enderdragon_Face.png
Status:Bad, Approachable
Drops:Overworld Portal
Produce:Eggs(Randomly)
Pet Food:Unknown

New Mobs will be added soon.
Thank you Minecraft Wiki for all the help.