Special Weapon Effects (Borderlands 2)

Pistols & Revolvers

 * Law: 100% Accuracy and recoil reduction while zoomed. (Quest Reward, "Won't get fooled again")
 * Teapot: Corrosive effect spreads to nearby enemies and Burst fire 2 when zoomed in.(Quest Reward, "You Are Cordially Invited: Tea Party")
 * Shoots two bullets at once, does additional Critical Hit damage (Can be found as Revolver and Repeater. Dropped by second assassin in Assassinate the Assassins)
 * Unkempt Harold: Fires 3 bullets which split into several mini rockets on a horizontal plane
 * Miss Moxxi's Rubi: High elemental chance, reward from Moxxi (Quest Reward)
 * Fibber: Inaccurate stats displayed. Flavor stats +50% love, +3000% damage. Actual behavior is highly variable - may fire one projectile or several; shots may ricochet; if they do, ricochet hits may do substantially increased bonus damage; shots may also travel at slow speed when several are fired, if so 7 are fired for high damage - but will be constant for any given instance of the weapon. (Quest reward from Mal in Eridium Blight)
 * Veritas: +10% duration to Fight For Your Life for every Aequitas or Veritas equipped in the party. (Quest Reward, "Clan Wars: Wakey Wakey") 
 * Flynt's Tinderbox: High chance to cause fire effect and bullets will travel in an arc.
 * Gwen's Head: Burst fires 9 instead of 3
 * Hornet: Burst fires five rounds. High Elemental Effect: Unknown
 * Maximized Lady Fist: Deals 10X damage on crit. High magazine count. (Quest reward, "Uncle Teddy")
 * Thunderball Fist: shots fire a blue orb which does shock damage and explodes after a few seconds.
 * Dahlminator: Fires homing & ricocheting projectiles that stick to the enemy and explode (usually Corrosive) (Quest reward, "The Lost Treasure")
 *  murduerer's Gub: Unknown effect. (Dropped from Laney, "The Cold Shoulder")
 * Infinite ammo, does not need to be reloaded. Also shoots a pattern which shows the symbol of infinity.
 * Gunerang: Reloading throws the gun like a boomerang. Drop off Rakkman in The Fridge.
 *  Earnest Logan's gun: -30% weapon accuracy, - 10% weapon recoil reduction, consumming 2 amm per shot, hightly effect vs Flesh (Causing explosive effect too, but seems having chance to penetrating body)

Shotguns

 * Thre Dog: Three barreled shotgun. (Dropped by Assassin Rouf during Quest "Assassinate the Assassins").
 * Consumes 3 ammo per shot, ridiculous high damage and number of pellets. Pellets fire in an inverse Y shape.
 * Miss Moxxi's Heart Breaker: Fire damage and +50% critical damage. Shoots in a heart pattern. (Quest Reward, "Safe and Sound"). "I just want to start a flame in your heart" reference to the song of the same name by the inkspots, featured in Fallout 3. When holding this weapon any elemental damage-over-time you deal causes you to gain health.
 * Asset Shotgun 1340: Has Hyperion Loader voice. (Quest reward, "Out of body experience")
 * Conference Call: Low-pellet-count, high-damage shotgun whose pellets move at a very high speed (Almost instant) and ricochet.
 * Sunny Blockhead: Deals fire damage. Fires 9 pellets in a square formation. Pellets ricochet off walls.
 * Octo: fires 8 pellets in 3x3 pattern with centre left pellet missing. pellets are slow moving and fly in an Sine-Wave pattern while leaving yellow orange trails.
 * RokSalt: Very fast reload speed. (Quest Reward, "Splinter Group")
 * Landscaper: Fires four projectiles in a trapezoid pattern that attach to a surface and explode after a short duration.
 * Sinewy Flakker: Fires many projectiles in a flak-like pattern which travels slowly in the direction the user is facing (Randomly found after defeating a boss enemy or as the Item of the Day in stores)
 * * Striker: High Accuracy, very low spread. +70% crit damage (Found by killing Old Slappy / Random drop) see striker, version referenced here is the "barbed" striker, with +50% melee damage.
 * Sledge's Shotgun: (Slot machine: 3 Vault symbols) or (Drop from killing Smash Head)
 * Deliverance: Obtained from Slot machine: 3 Vault Symbol Jackpot or a rare drop from Tumba. When shotgun is thrown for reload, if any enemies are present, the gun will home in on the enemy and explode. Otherwise, the gun will fly in a straight line. The gun will bounce on any material object that is not an enemy until it either times out (~5 seconds) or hits the target.
 * Tidal Wave: Fires 7 horizontal slow moving projectiles in a wave pattern that richochets off of surfaces once if it does not hit an enemy. (Quest Reward, "Uncle Teddy")

Combat Rifles

 * Feral Veruc: Spread decreases while zoomed. (found off a named NPC on "The Good, the Bad, and the Mordecai") Reference to Veruca Salt, the spoiled rich girl from Charlie and the Chocolate Factory.
 * Unknown effect.(has chance to cause different types of elemntal damage, corrosive and electric, also the gun can be orange? or blue)
 * Scorpio: Occasionally fires multiple rounds. Extra shots still consume ammo, and may proc to a random element. (Quest reward, "Bearer of Bad News")
 * Shoots high velocity explosive bullets (from hip and sights). Has custom skin, covered in doodles and stick figure art. On reload, has a random chance (10% maybe?) to make a sound and triple its magazine size (can just fire one shot and reload until you get it). Shots fired from this mag do roughly 10x normal damage and have a faster fire rate. This effect goes away if you switch weapons. (Quest reward, "The Chosen One").
 * Bullet Hail: Bullets are fired at a 45 degree angle upward, causing the bullets to land ~30 meter away minimum unless aiming down into the floor. The rounds also split into two projectiles after some distance and resemble fireworks when shot for prolonged periods. Its normal non-zoomed sight is also switched to a range markers one with no actual cross-hair. (The Emperor Ming, Flash Gordon: "Klytus, I'm bored. What plaything can you offer me today?" "Hot hail" is one of the disasters Ming then inflicts on Earth.) (Quest reward, "Bandit Slaughter: Round 5")
 * Higher Crit Damage. Has custom skin. (quest reward)
 * Plump KerBlaster: Fires a grenade, instead of bullets, that explodes on contact, dropping a grenade that deals damage as the fired grenade.
 * Speed Kills:very fast spooling weapon, very large magazine.

Sniper Rifles

 *  Chikamin Buffalo: very high damage and accuracy as well as increased stability, but slow RoF and lacks a scope. (Quest reward)
 * Fremington's Edge: Increased zoom level. (Dropped from Reeth the Assassin during Quest "Assassinate the Assassins")
 * Trespasser: Ignores shields. Callback to Mordecai's Trespass skill from Borderlands 1, which gave up to a 100% chance to ignore shields. (Quest reward for Animal Rights)
 * Burst fire sniper rifle with slow moving rounds
 *  Pitchfork: 5 Horizontal Shot Burst Fire. (Reference to the online music magazine Pitchfork, notorious for giving bad reviews to "mainstream" music.) (Slot reward for getting the Vault Symbol jackpot)
 * Volcano: fire damage bonus, fire effect spreads to nearby enemies (random drop)
 * Morningstar: Annoying, guilt-tripping voice on reload, kill, or critical hit. Storing gun also does annoying voice which plays at random intervals. (Quest reward, "Hyperion Contract #873")
 * (Translated: I am delighted, Where is the library?): Sends out healing beams on hit, like Transfusion grenades. (Quest reward, "Hyperion Slaughter: Round 5")
 *  Lyuda: Fires a trio of projectiles in a horizontal pattern for the cost of 1 bullet. Increased critical hit damage.
 * Increased critical hit damage
 * Fires five shots in burst
 * Longbow: (Translated: This is not a Sniper Rifle) Scopeless, fire damage, and fires a slow, arcing projectile which leaves pixelated trail (resembling the arrows in Minecraft).

Rocket Launchers

 *  Bonus Bunny: When reloaded the gun bounces along the ground in a forward-random direction similar to a rubberized grenade. (found off spiderant)
 *  gaa dunk ga Nukem: When fired, the rocket simulates a small Nuclear blast (Duke Nukem reference)
 * uses 2 ammo per shot. Fires a large rocket which in turn fires off smaller rockets as it travels. In the description, states 'consumes less ammo per shot. Just kidding! no it doesn't.'
 *  Big Roaster: Drastically increased rocket speed (nearly instant at mid range) (this effect may be incorrect, obtained Big Roaster without increased rocket speed), 3 rockets per shot. (Quest reward, "Note for Self-Person")
 *  Pyrophobia: Causes the rockets to continuously explode during their flight.
 * Big Badaboom: Fires 6 rockets simultaneously at the cost of 1 rocket ammo.
 * Miss Moxxi's Creamer: High rocket velocity, rocket splits in two after a certain distance (Reward, Creature Slaughter Dome Round 5)
 * Hive: Consumes 4 ammo per shot. Fires a stationary "beehive" that emits small homing rockets.

SMGs

 * Bane: Slows movement, highly inaccurate, produces Psycho Midget noises when switching to it, firing, and reloading.
 * Miss Moxxi's Bad Touch: While wielded, any elemental damage-over-time you deal returns health.
 * Miss Moxxi's Good Touch: When held the controller vibrates, does highly increased critical and Fire Damage
 * Lascaux: 9-round burst fire while scoped; always has a Double mod and +100% recoil reduction. The fire pattern is fixed, resembling a bull. The crosshairs display an area much smaller than the firing pattern. (always found in Frostburn Canyon)
 * Feculent Chulainn: Fires rounds that has procs both shock and slag, player is slagged when equipped. (Quest reward, "Clan Wars")
 * Recoil lowers as you fire.
 * Baby Maker: Gun explodes like a small mirv grenade when thrown.
 * Emperor - When zoomed, fires 6 shot burst.
 * : High fire damage that stacks and triggers on every shot. Most likely a reference to the "We don't need no water..." effect from the first game.
 * Bitch: reference to Legendary weapon in BL1. Unknown effect, but has high accuracy.
 * redy Bone Shredder: Consumes 2 ammo per shot with low accuracy.(effect unknown) sometimes drops from Bone Head 2.0.
 * Very large clip and shoots 3 bullets at once.
 * Hellfire: possibly same effects as BL1, can be dropped by killing Scorch, other locations unknown. (if anyone has more info. on Hellfire, please feel free to edit this description)

Shields

 *  Order: When a "Law" type revolver is equipped, any melee damage done is converted to health. Also deals roid damage when shields are depleted. (Quest Reward)
 * Flame of the Firehawk: Constant fire nova effect while shields are at 0. This effect lasts indefinitely, as long as your shield remains at 0, triggers roughly every two seconds. (Quest reward, "Cult Following; The Enkindling")
 *  Love Thumper: High roid damage. Low recharge rate and very high recharge delay. Melee attacks create a Nova-like explosion while the player is buffed by its roid damage. (Quest reward, "Best mother's day ever!")
 *  Deadly Bloom: Has fast recharge rate with a very powerful nova on shield loss or entering fight for your life mode. The nova on shield loss follows the usual normal mechanic, and will not trigger again until the shield is recharged, but the nova on entering Fight For Your Life will trigger every time. (Quest Reward, "Helping Out Overlook") [reference to the movie The Last Starfighter]
 *  Aequitas: +10% duration to Fight For Your Life for every Aequitas or Veritas equipped in the party. (Quest Reward, "Clan Wars: Wakey Wakey")
 *  The Sham: Abnormally high bullet absorb rate. (When a shield absorbs the bullet, you take no damage from it. - 80% was the one I got.)
 * Tortoise: Very high capacity, lowers health and movement speed when active, raises movement speed when depleted. Likely a reference to "The Tortoise and The Hare."
 *  Neogenetor: Has health regen and very high +max life. The lower your shields are, the higher the health regen. Stops regeneration when shields are empty. (Appears to be drop from quest mob during Monster mash part 3)
 *  1340 Shield: Low bullet absorb rate, high capacity, decent recharge rate and delay. Has Hyperion Loader voice. (Quest reward, "Out of Body Experience")
 * Whisky Tango Foxtrot: Has a chance of dropping explosive IEDs and shield boosters on hit, explosives damages both allies (including the player) and enemies. The name is a reference to the NATO phonetic alphabet, where "Whisky Tango Foxtrot" is a representation for "WTF". The text, including "...all foxtrotted up" on the IED itself, is an expansion of the acronym "SNAFU".
 * The Bee: Extremely high Amp damage bonus. Extremely low Amp Shot Drain.
 *  Impaler: Launches Corrosive homing spikes when damaged with bullets. Deals Corrosive Spike Damage to melee attackers.
 *  The Cradle: When shield depletes, has a chance to instantly drop the player in Fight For Your Life mode. Drops from Henry. Tediore shield that explodes like the guns.
 * Black Hole. Pulls nearby enemies towards you when shields are depleted; similar to the effect of singularity grenades.

Grenade Mods

 * Bonus Package: Spawns a second set of child grenades after the first set explodes. Drop from Boom and Bewm.
 * Kiss of Death: Homing elemental grenade that latches onto target's face until they die or grenade banishes. Upon exploding sends out healing beams as if from a transfusion grenade (Quest Reward: Hell Hath no Fury)
 * Fuster Cluck: Causes grenades to spawn from the one thrown rapidly while it travels through the air. (Quest Reward, "The Pretty Good Train Robbery")
 * Nasty Surprise: Teleports and splits into four child grenades near the feet of multiple enemies in front of the player.
 *  Rolling Thunder: When thrown stays low to ground and has an explosive bounce. Can not hit high rose enemy and wont jump over small gaps between land. (Wilhelm can drop it)
 *  Storm Front: Initial explosion spawns a 'fork' which shoots out a few child grenades. The fork creates an aura that has no noticeable effect besides visual. The fork attacks any enemies that wander near it for shock damage. The child grenades also attack enemies near them with a smaller range and slightly less damage. The fork and child grenades explode for additional damage when finished.
 * Pandemic: Corrosive Spawns three homing grenades after initial explosion.
 * Sticky Homing fire leech: After the first set explodes it spawns a second set of child grenades which has a high burn Dam per sec.
 *  E=mc^(OMG)/wtf  Homing Electrical Singularity: Homes in on target after thrown. Pulls in enemies around it, causing period damage until it explodes for massive damage.
 * Seems to act like a sprayer type grenade in that when it detonates, it starts spinning and releasing fire, as well as smaller mirv style explosives during.
 * Contraband Sky Rocket - Deals an insane amount of fire damage based on your level in a mirv style firework explosion. Grenade travels upward in an arc, and will significantly bounce back down when it hits a ceiling. Best used indoors (Despite the "Warning"). All characters made will start with this grenade mod if the owner used the code that comes with either of the special editions of the game.
 * spawns multiple mini-grenades that home in and stick to a target dealing constant elemental damage.

Relics

 *  Deputy's Badge: Increases shotgun damage and reload speed or Increased Pistol Damage and Fire Rate, Increases Fight for Your Life Time by 10% for every player equipped with a Deputy's Badge (Quest reward, "Showdown")


 *  Sheriff's Badge: An upgraded version of the Deputy's Badge. Increases Fight for Your Life Time by 15% for every player equipped with a Deputy's Badge. Dropped by The Sheriff of Lynchwood
 * Blood of Terramorphous: Unknown effect - May increase the rate at which varkids evolve into Vermivorous the Invincible. Drops from Terramorphous.