Repair

Pet Battle: [17-18] Winterspring

Profession: Archaeology - Dwarf

Artifact: [Clockwork Gnome]

Pet Battle: [18-20] Blade's Edge Mountains

Profession: Cataclysm Engineering [25]

Taught By: Gnomish Engineering Trainers

Scenario: Island Expeditions

Approximate Drop Rate: Unknown

Pet Battle: Operation: Mechagon (Dungeon)

Trading Card Game: Worldbreaker

Profession: Engineering [265]

Taught By: [Schematic: Lifelike Mechanical Toad]

Pet Store 

Profession: Engineering [75]

Taught By: [Schematic: Mechanical Squirrel]

Vendor: Rillie Spindlenut

Zone: Icecrown

Cost: 40 (unlimited supply)

Profession: Cataclysm Engineering [25]

Taught By: Goblin Engineering Trainers

Drop: Void Reaver [??+]

Zone: Tempest Keep

Approximate Drop Rate: 1 in 13

Pet Battle: [3-6] Azshara; [5-7] Stonetalon Mountains; [17-18] Winterspring

Drop: Assembly of Iron [??+]

Zone: Ulduar

Approximate Drop Rate: Unknown

Drop: Brutallus [??+]

Zone: Sunwell Plateau

Approximate Drop Rate: 1 in 20

Pet Battle: [3-4] Westfall

Profession: Junkyard Tinkering

Taught By: [Blueprint: Utility Mechanoclaw]

Zone: Mechagon