I am referring to items that are not produced by a company with the Transformers license (Hasbro/Takara), but are original items that are not "knockoffs" of any existing mold. They tend to improve functionality of Hasbro/Takara products. Examples include the Justitoys trailer and gun attachments for the Masterpiece series and TF-Lab's Classics Cliffjumper accessories and head. Expansion sets? Third-party add-ons? Unofficial playsets? Upgrade kits?