Wanted posters are objects that have been featured in Shrek and Shrek Forever After. They were used to let pubic villages or kingdoms be aware of criminals lurking around. However, most of the characters that are indeed wanted never really did anything wrong and were simply victims of Farquaad's fairy tale removal act.
In the opening, Shrek is seen on a wanted poster demanding that ogres be found dead or alive. Among that are other posters for characters such as Pinocchio, The Three Little Pigs, the Elves, and the Fairies.
It is shown in this film that Shrek had kept one of his old wanted posters, back when he was a "real ogre". Later in the alternate universe, he finds himself wanted once again, except he's one of many other ogres (including Fiona) that are being targeted by the authorities.
Several wanted posters of Puss in Boots appear throughout the film. They have a different design and art style compared to those seen in the Shrek movies, more closely fitting the Spanish aesthetic.
Wanted posters are major collectibles in the game, granting access to players who collect three of them. In the story, the fairy tale characters are still being wanted, and Donkey tells Shrek to help take them down. He encourages him to start a collection, saying "it'll probably be worth something one day". Characters such as Pinocchio, The Big Bad Wolf, as well as early versions of The Pied Piper, Rumpelstiltskin and Humpty Dumpty appear on these posters. However, all of the other posters feature characters never seen in the movies (i.e. Chicken Little, The Hare, Georgie Porgie, etc.).