completist

1. (originally science fiction fandom slang) A collector who strives to obtain a complete collection of some type of thing, especially a fan who aims to own or consume the complete output of a particular author, publisher, musician or band.Examples: "completist - A dope who tries to have a complete collection in some line. The line may be as broad as having all the prozines ever published, or as narrow as collecting all the Golden Atom tales or all official correspondence during one's incumbency in some office. […]"; "Ozzie Train, secretary. Ozzie needs little introduction, other than that he is the remaining half of Prime Press, and a genuine completist."; "There's no new material on it, just previously issued bits and pieces. That rules out the completist collector. Go figure."