Borderlands 2 Cheats

Phased and Confused (Bronze): Phaselocked 100 enemies.
So Much Blood! (Bronze): Gunzerked continuously for 90 seconds.
Cute Loot (Bronze): Killed a Chubby.
Tribute To A Vault Hunter (Bronze): Got an item from Michael Mamaril.
Definitely An Italian Plumber (Bronze): Killed Donkey Mong.
High-Flying Hurler (Bronze): Killed a flying enemy with a thrown Tediore weapon.
Token Gesture (Bronze): Redeemed 25 tokens.
Unseen Predator (Bronze): Remained in Zero's Deception mode for ten seconds straight.
Build Buster (Bronze): Killed a Constructor without it ever building another bot.
How Do I Look? (Bronze): Unlocked 10 customization items.
Friendship Rules (Bronze): Revived someone from "Fight for Your Life!" that is on your friends list.
Better Than Money (Bronze): Purchased 5 items from the black market.
Up High, Down Low (Bronze): Gave Claptrap a high five.
Bounty Hunter (Bronze): Completed 20 side missions.
Did It All (Silver): Completed all side missions.

DLC: Captain Scarlett and Her Pirate's Booty
There are 3 Trophies - 1 Gold, 1 Bronze, 1 Silver.

Completionist (Silver): Completed all Pirate's Booty side missions.
Gadabout (Bronze): Discovered all named locations in Oasis and the surrounding Pirate's Booty areas.
Treasure Hunter (Gold): Completed the mission "X Marks the Spot"

Item Duping
Place the desired item(s) on a character, and ready or create a second character to take on as many of the item as you wish. Start a two-player co-op game with the first character as player 1 (and the other character as player 2, obviously). Give desired item(s) to player 2 and have player 2 save and leave game. Quit game from PS3 system menu. Because the game doesn't save player 1 when player 2 leaves, nor when you quit from the system menu, now both players have said item(s). Repeat as desired (for faster duplication, transfer all copies of the item to player one, save-and-quit with both, and start over with the duplicates on player 1).
Badass Rank Farming
To build a high Badass Rank, and gain all the perks associated with it, create a pair of new characters in co-op mode and have player 1 beat player 2 in 50 duels. This gives 166 Badass Ranks. Save and quit, then start another new game, creating another new character for player 1 (don't bother messing with player 2's character). Fight another 50 duels, with player 1 winning them all for 166 more Badass Ranks. Repeat as desired, and delete the pile of unwanted characters when you're done.. If you set the controller configuration to something where you can just keep tapping the melee-attack button without ruining your aim at the other player, you can finish a duel-run like this in roughly 10 minutes. Thus, over the course of one hour, you can build up 996 Badass Ranks.

Allowing secondary characters to reach level 20 easily. [Flesh-Stick]
When you have a character reach Tiny Tina do all of her side missions until you make it to the final stage of her tea party. Here she wants you to lure Flesh-Stick to her little cove to join her tea party. Since you can fail this mission by killing him you can actually repeat that over n over for experience. On top of that if a second controller is available and you wish to make another character but don't want to level them up the normal way you can have that created person join your session and have them run all the way to Tiny Tina. If you keep them in front of her and your main character in front of where Flesh-Stick walks out you can kill him and re-accept the mission as fast as your trigger finger allows making anyone reach roughly 20-21 in a matter of minutes.

Carry one more item in your backpack
You must have 2 class mods for this to work. Once your backpack is full, switch your currently equipped class mod for another one in your backpack (you can then re-equip your original class mod after you've done this). Then exit the backpack menu and you can now pick up one more item and have a backpack with 28 items in it instead of maximum 27.

Extra Wub
To unlock extra wub, go to the title screen (where it says push start) and do the konami code, up up down down left right left right O X start. Under gameplay it will unlock extra wub, but sorry, it does literally nothing.

Trophies: Captain Scarlett and Her Pirate's Booty DLC
There is 1 Bronze Trophy, 1 Silver Trophy, and 1 Gold Trophy.

Completionist (Silver): Completed all Pirate's Booty side missions.
Gadabout (Bronze): Discovered all named locations in Oasis and the surrounding Pirate's Booty areas.
Treasure Hunter (Gold): Completed the mission "X Marks the Spot"