When it comes to collecting, there are a variety of synonyms for the term "collector's". One such synonym could be "curator", which also implies a level of care and attention to detail in selecting and maintaining pieces for a collection. "Aficionado" might be another term, indicating a deep passion and knowledge about a particular type of collection. "Hobbyist" also fits the bill, suggesting that collecting is a pleasurable pastime rather than a serious pursuit. Other options include "enthusiast", "connoisseur", or even "hoarder" - although the connotations of the latter term may be less positive than the others!