From WoWWiki

A type of creature or mob in the game as distinguished from the fleshy type. This includes most constructed creatures except some Elementals (like Golems) and Undead (like Flesh Golems).

Most mechanicals are found in Gnomeregan, and most can be controlled using the Gnomish Universal Remote. Not having blood as such, most Mechanicals are Immune to bleed type melee attacks: Rend, Garrote, etc.

Examples of Mechanicals

• Alarm-O-Bots
• Bomblings
• Explosive Sheep
• Fel Reavers
• Gnomish Mechs
• Harvest Golems
• Lifelike Mechanical Toads
• Mechanical Chickens
• Mechanical Dragonlings
• Mechanical Greenchs
• Mechanical Squirrels
• Mechanical Yetis
• Mechanized Guardians
• Mechanized Sentrys
• Spider Tanks
• Shredder

Sentient Races and Species
Alliance	Draenei • Dwarf (playable) • Gnome • Human (playable) • Night elf
Horde	Blood elf • Undead (playable) • Orc (playable) • Tauren • Troll (playable)
Azeroth	Ancient • Centaur • Dark troll • Dark Iron dwarf • Dragon • Dryad • Earthen • Elf • Faceless One • Forest troll • Furbolg • Gnoll • Goblin • Harpy • Half-elf • Half-orc • High elf • Highborne elf • Ice troll • Iron dwarf • Jungle troll • Keeper of the Grove • Kobold • Leper gnome • Magnataur • Makrura • Murloc • Naga • Nerubian • Pandaren • Qiraji • Quilboar • Satyr • Taunka • Treant • Trogg • Tuskarr • Vrykul • Wildhammer dwarf
Outland	Arakkoa • Broken draenei • Fel orc • Gronn • Half-ogre • Lost One • Nether drake • Ogre • Ogre mage • Ogre Lord • Rock flayer • Sand gnome • Sporeling
Burning Legion	Annihilan • Ered'ruin • Gan'arg • Man'ari eredar • Mo'arg • Nathrezim • Sayaad • Shivarra • Tothrezim • Wrathguard
Creatures	Beast • Critter • Demon • Dragonkin • Elemental (Air, Earth, Fire, Water, Conglomerate) • Giant • Humanoid • Mechanical • Undead • Uncategorized creature
Miscellaneous	Ethereal • Naaru • Titan • Worgen