Battle Pets by Zone

Pet Battle: [1-2] Dun Morogh; [1-2] Durotar; [3-4] Northern Barrens; [7-9] Northern Stranglethorn; [9-10] Southern Barrens; [16-17] Blasted Lands; [17-18] Hellfire Peninsula; [18-19] Nagrand (Outland); [25] Spires of Arak; [25] Nagrand (Draenor)

Pet Battle: [1-2] Durotar; [6-7] Wetlands; [11-12] The Hinterlands; [15-16] Burning Steppes; [15-16] Un'Goro Crater; [22-23] Icecrown; [23-24] Twilight Highlands; [25] Gorgrond

Pet Battle: [1] Orgrimmar; [1-2] Durotar

Pet Battle: [1] Orgrimmar; [1-2] Durotar; [23-24] Uldum

Drop: Hellscream Laborer [35], Kor'kron Marauder [35], Mercenary Engineer [35]

Zone: Northern Barrens

Approximate Drop Rate: 1 in 6,600

Pet Battle: [1-2] Durotar; [7-8] Arathi Highlands; [11-12] The Hinterlands

Pet Battle: [1] Orgrimmar; [1-2] Durotar

Pet Battle: [1] Gilneas; [1] Orgrimmar; [1-2] Durotar; [1-2] Eversong Woods; [1-2] Dun Morogh; [1-2] Teldrassil; [3-6] Silverpine Forest; [3-6] Ghostlands; [4-6] Ashenvale; [6-7] Hillsbrad Foothills; [6-7] Wetlands; [12-13] Dustwallow Marsh; [14-15] Felwood; [14-15] Swamp of Sorrows; [18-19] Nagrand (Outland); [20-22] Howling Fjord; [23-24] Twilight Highlands; [25] Nagrand (Draenor)

Pet Battle: [1] Orgrimmar; [1-2] Durotar; [6-7] Wetlands; [14-15] Swamp of Sorrows; [23-24] Twilight Highlands