The Crazy Gang of mainstream Marvel Earth (Earth-616) first appeared in Marvel UK's The Mighty World of Marvel #10 (March 1984), by Alan Moore and Alan Davis. They subsequently appear in Captain Britain Comics #1-3 (January-March 1985).
The Crazy Gang first appeared in American comics in Excalibur #4 (January 1989), by Chris Claremont and Alan Davis. They subsequently appear in #52 (July 1992), #54 (September 1992), #57-58 (November-December 1992), and #124-125 (September-October 1998).
The Crazy Gang received an entry in the Official Handbook of the Marvel Universe Update '89 #2.
Back on his homeworld, Earth-616, Captain Britain encountered his world's Mad Jim Jaspers. Jaspers was even more powerful here and in a moment of boredom he created the Crazy Gang from the Earth. Jim Jaspers was killed shortly afterwards and his death undid most of the changes Jaspers had done to the world, but the Crazy Gang continued to exist for some reason. Leaderless, the Crazy Gang tried to rob banks, but without a leader they were too incompetent to be any actual threat. They started looking for a leader and Slaymaster responded. Disguised as the Caterpillar from Alice's Adventures in Wonderland, he convinced the Crazy Gang that he was like them. Under Slaymaster's leadership, the Crazy Gang became an effective band of thieves and he directed them to steal and vandalize objects and monuments that had symbolic importance to Great Britain. These actions angered Captain Britain and he attacks the Crazy Gang, walking into the trap Slaymaster set for him. Finding out that Slaymaster had used them, the Crazy Gang left him, disappointed.
Months later, they were hired by Arcade to kidnap Courtney Ross, Captain Britain's former girlfriend. In Arcade's deadly theme park Murderworld, the Crazy Gang fought Captain Britain's new group Excalibur. Crazy Gang member Tweedledope had created a device that allowed the Crazy Gang to switch bodies with Excalibur, but in the end Excalibur managed to restore everything back to normal.
Disappointed with their life of crime, the Crazy Gang kidnapped Joyboy of the Technet, now known as the N-men. They brought Joyboy to their Red Queen and Joyboy's ability to twist a person's dreams and desires and make them a nightmarish reality connected with the Red Queen's madness. The two entered a symbiotic embrace and created a beautiful land. They invited villagers from nearby to visit them and the villagers accepted. Their sudden disappearance was noticed and Excalibur was called in by their long-time ally Dai Thomas. Excalibur discovers the Wonderland, but Captain Britain's prejudices against the Crazy Gang made him attack the group (and they were attacked by the land itself). His girlfriend Meggan convinced him, though, that the Crazy Gang had changed their ways and was actually harmless, and Excalibur leaves the Crazy Gang as friends. The citizens of the land, mostly seniors, were allowed to enjoy this new paradise. Some time later, Excalibur sends a large group of trolls, who were living under London, to live with the Crazy Gang in their Wonderland.
Under unknown circumstances, Joyboy returned to the Technet and the Red Queen turned insane again. The Executioner was destroyed and the Crazy Gang buries it. Former Excalibur member, Feron, stumbles upon the Crazy Gang. Falsely believing his old friends did not care about him anymore, Feron disguises himself as the Executioner. He manipulates the Crazy Gang to attack Excalibur, but they were easily defeated and the Executioner was unmasked. The Crazy Gang was then invited to Captain Britain's wedding to Meggan.