Straw Hat Pirates/Allies

Throughout the series, there have been people who either traveled with one or all of the Straw Hat Pirates for a short period of time or aided them in one way or another. Many of these individuals would be considered temporary pirates in a way. Along with those individuals, there have also been various groups that have assisted the Straw Hats in their adventures. These groups have helped the Straw Hats either to reach a certain goal or to defeat a common enemy.

Straw Hats-Franky Family-Galley-La Alliance
An alliance formed on the way to Enies Lobby to rescue Nico Robin and Franky from the World Government, as well as retaliate against CP9 for the assassination attempt on Iceburg. The majority of the help occurred in the courtyard and courthouse in order to help the Straw Hats reach the Tower of Justice and face the CP9 agents, with the Franky Family entrusting the rescue of their leader to the pirates. The allies went their separate ways when the Straw Hats continued their journey with Franky as their new Shipwright, and the Franky Family started working for Iceburg and the Galley-La Company. This alliance is aided by Kokoro, Chimney, Gonbe, Yokozuna, Oimo, Kashi, Iceburg and Usopp under the alias "Sogeking".

Straw Hat-Heart Alliance
An alliance between the Straw Hat Pirates and the Heart Pirates formed on Punk Hazard by their two captains in order to defeat Kaido, one of the four Yonko of the New World. According to Law, who proposed the alliance, their cooperation would give them a 30% chance to defeat the Yonko. The plan was to destroy Kaido's source of SMILE delivered by Doflamingo, weakening him while letting Doflamingo take on Kaido's anger. However, the events on Dressrosa made Law concerned about Kaido's reaction. The alliance eventually would grow to became the "Ninja-Pirate-Mink-Samurai Alliance" on Zou. This alliance is aided by Kin'emon, Momonosuke, Kanjuro, and an unwilling Caesar Clown, and briefly by the G-5 marines under Vice Admiral Smoker and Captain Tashigi, the kidnapped kids used for Caesar experiments, and Brownbeard on Punk Hazard, and by the Corrida Colosseum fighters including the Straw Hat Grand Fleet members, Elizabello II, and Dagama, the Riku Family, the citizens of Dressrosa and Green Bit, a representatives of the Revolutionary Army, and Admiral Fujitora on Dressrosa.

Ninja-Pirate-Mink-Samurai Alliance
An alliance of the Kozuki Family retainers with the Straw Hat-Heart Alliance formed on Zou in response to Momonosuke's request for the pirates to help him avenge his parents against the Beasts Pirates and the shogun of Wano Country and release Wano from their control. The alliance attack is postpone until Sanji rescue mission from the Big Mom Pirates. Nekomamushi has shown interest in finding and recruiting Marco and the remaining Whitebeard Pirates. This alliance is aided by the entire Mink Tribe, through its leaders, Zunisha, and the Kozuki Family allies and rebels from Wano.

Individuals
Among those, there are more notable people:


 * Vivi and Carue, as they traveled with the crew for almost the entire Alabasta Saga, and even considered permanently joining them but due to her promise it seems that she is always welcome back.


 * Jinbe, who was invited to join the crew, but declined due to unfinished business. He promised that once his business is concluded, he will return to the Straw Hats, and join them if they still want him.
 * Trafalgar D. Water Law, who has formed an alliance with Luffy to take down the Yonko Kaido. Law has traveled with the Straw Hats since they left Punk Hazard

Groups
Among those, there are more notable groups:
 * The Whitebeard Pirates and their allies, who despite only allied themselves with Monkey D. Luffy in Marineford due to the order of the captain, continue to protect him saying that they will fulfill their father final order.
 * The Heart Pirates who formed the first pirate alliance with The Straw Hats.
 * The Kozuki Family and Mink Tribe who later joins them to form the Ninja-Pirate-Mink-Samurai Alliance.
 * The Straw Hat Grand Fleet who increase The Straw Hats' power and reputation in the New World.