Shock
A shock is a sudden effect, but is not limited to the classic electric shock. There are many different shocks in the game, all of them representing a certain element and damage caused by it.
Shaman
The three Shock spells are the main source of magic damage for the shaman at close range. All shaman shocks deal instant direct damage but are usually not very mana-efficient and have a shared cooldown.
[Earth Shock]: Instantly shocks the target with concussive force, causing Nature damage and reducing melee and ranged attack speed by 20% for 8 sec.
[Flame Shock]: Instantly sears the target with fire, causing Fire damage immediately and further Fire damage over 18 sec.
[Frost Shock]: Instantly shocks the target with frost, dealing Frost damage and slowing movement speed. Lasts 8 sec. Causes a high amount of threat.
Originally, 
[Wind Shear] was known as Wind Shock, and was the fourth Shock. It was renamed in patch 3.0.2, and no longer shares a cooldown with the other Shocks.
Paladin
Holy Paladins have a unique shock for both offensive and defensive situations:
[Holy Shock]: Blasts the target with Holy energy, causing Holy damage to an enemy, or healing to an ally, and grants a charge of Holy Power.
Others
Hunter pets
[Nether Shock] (Nether ray ability): Instantly lashes an enemy, interrupting spellcasting and prevents any spell in that school from being cast for 2 sec.
Tinkers
- Painful Shock is caused by the 'Plasma Misfire!' backfire effect from a
[Grounded Plasma Shield], taunting all enemies within 40 yards for 4 sec.
Mobs and NPCs
The vast majority of Shock spells in the game are unavailable to players, but are used by mobs or NPCs. Often, several versions of each spell exist, with each type of mob having its own version. The following is a reasonably complete list, as of patch 4.3.0, sourced from Wowhead and Buffed.de.
- Arcane Shock is used in various forms by a number of mobs, including Vexallus and Kiggler the Crazed
- Aural Shock is used by Dark Screechers in Blackrock Depths
- Concussive Shock is used by Frostwarden Handler in Icecrown Citadel
- Deep Shock (not to be confused with Deep Shock)
- Earth Shock is used by around 50 types of mobs and NPCs
- Electro Shock, Electro-Shock, Electroshock, Electro-Shock Therapy and Electrical Shock are used by several mobs
- Fel Shock
- Felfire Shock is used by Wrath-Scryer Soccothrates in The Arcatraz
- Flame Shock is perhaps the most ubiquitous Shock in the game, being used in various forms by more than 60 different types of mobs and NPCs
- Frost Shock is used by more than 50 different types of mobs and NPCs
- Ground Shock is used by Stonecore Earthshaper in the Stonecore
- Holy Shock is used by about 11 different mobs and NPCs
- Lightning Shock is used by Forged Iron Troggs in the Halls of Stone, and also by Bound Zephyrs in the Bastion of Twilight
- Mind Shock is used by Sunseeker Researchers in the Botanica
- Nature Shock is used by Bloodwarder Greenkeeper in the Botanica
- Nether Shock is used by a number of mobs
- Poison Shock is used by a number of mobs
- Sentry Shock is used by Charged Sentry Totem in the Grizzly Hills
- Shadow Shock is used by numerous mobs, and NPCs such as Vol'jin
- Shell Shock is used in 2 very different forms by various mobs in Vashj'ir and by Tempest-Smiths in Tempest Keep
- Shock is used by various mobs and NPCs
- Shock of Sorrow is used by Maiden of Grief in the Halls of Stone
- Sonic Shock is used by Murmur in the Shadow Labyrinth
- Spell Shock is used by a number of mobs
- Spirit Shock is used by Essence of Desire in the Black Temple
- Star Shock
- Static Shock used by mobs including Al'Akir in the Throne of the Four Winds
- Time Shock is used by Tempus Wyrms in the Dragonblight
- War Shock
- Wind Shock is used by certain mobs
Related abilities
The following mob or NPC abilities also involve shocks:
- Crimson Shockwave used by Crimsonborne Guardians in Grim Batol
- Empowered Shock Vortex used by Prince Valanar in Icecrown Citadel
- Flameshocker's Revenge
- Flameshocker's Touch
- Massive Shockwave used in different forms by Julak-Doom and Skullcrusher the Mountain in the Twilight Highlands
- Pulsing Shockwave
- Shock Barrier is used by Kael'thas Sunstriderin Tempest Keep and the Magisters' Terrace
- Shock Blast is used by a number of mobs
- Shock Defense
- Shock Charge
- Shock Grenade
- Shock Lance is used by Amber Drakes in the Oculus
- Shock Nova
- Shock Vortex is used by Prince Valanar in Icecrown Citadel to summon a Shock Vortex
- Shockwave is used by a huge variety of mobs and NPCs, as well as by Protection Warriors (
[Shockwave]) - System Shock is used by Emissary Roman'khan in Silithus
- Thundershock is used by certain mobs
- Twilight Shockwave is used by certain mobs