A Usermade Expansion Pack or UXP for short is an expansion pack made by a single designer or design team containing a variety of content. By definition, a User-Expantion must contain both animals and objects. It must be relesed or partial content is relesed. Because of this definition, many users or Groups can claim to be making a UXP however, to be considered a true User Expantion, it must be relesed or partialy avalible. A User Expantion normally contains graphics and images such as a box art.
Many UXPs have been made such as Paranoia!, ZooTycoon ABC AVES, ZooTycoon ABC REPTILIA, European Expeditions, Arabian Nights, Island Excursions, and Blue Planet. Radical Remake is considered a UXP to some, however it does not fit the difinition, becuase it has only has few contents of mods such as the Mustang, it is just revised content.