Thieves are really underrated. Not only can they steal your weapons and armor, but they can also steal the skin off your back. The Thief class can earn a skill called the Secret Hunt that allows you to steal animal skins. You can sell these poached items at the Fur Shop located in various towns.
Animal | Item | Ahriman | Magic Shuriken | Behemoth | Defense Armlet | Black Chocobo | Eye Drop | Black Goblin | Small Mantle or Hi-Potion or Antidote | Blue Dragon | Cashmere | Bomb | Fire Ball | Bone Snatch | Hi-Potion or Partisan | Bull Demon | Battle or Giant Axe | Chocobo | Phoenix Down | Cocatoris | Soft | Cuar | Soft | Dark Behemoth | Wizard Rod | Dragon | Jade Armlet | Explosure | Lightning Ball | Ghoul | Ether | Goblin | Potion | Great Morbol | Ice Sheild or Elixir | Grenade | Hi-Potion or Water Ball | Gust | Hi-Potion or Mind Gauche | Hydra | Blood Sword | Juravis | Potion | King Behemoth | Cherche (Always: Float and Reflect, Women's Perfume) | Living Bone | Wizard or Elf Mantle | Mind Flare | Hi-Ether | Minitaurus | Coral Sword | Morbol | Platina Messer | Ochu | NKai Armlet | Pisco Demon | Echo Grass | Red Chocobo | Barette | Red Dragon | Salty Rage (Always: Protect and Shell, Women's Perfume) | Revnant | Hi-Ether | Red Panther | Antidote | Sacred | Holy Lance or Ivory Rod | Skeleton | Holy Water or Ether | Squidlarkin | Small Mantle or Sleep Sword | Steel Hawk | Phoenix Down | Taiju | Defense Ring | Trent | Gold Staff or Fairy Harp (Attack Power: 15 Evade: 10% Range: 3 Add: Charm Equip: Bard) | Vampire | Holy Water or C Bag | Woodman | Eye Drop |