Pronoun Hoarder refers to a person who uses many sets of pronouns. When ones sees a new set of pronouns and feels like they fit, they will start using them. Soon their list of pronouns will become very long. A pronoun hoarder does not have to use all the pronoun sets they hear about.
Most of the pronouns one hoards tend to be nounself pronouns and other neopronouns, however they could use traditional pronouns as well.