Synonyms for Collection (same or very similar meaning)
WordNet sense 1 (several things grouped together or considered as a whole):
accumulation, aggregation, assemblage
WordNet sense 2 (a publication containing a variety of works):
compendium
WordNet sense 3 (request for a sum of money):
appeal, solicitation, ingathering
WordNet sense 4 (the act of gathering something together):
assembling, collecting
From the ODE community, based on WordNet
add/edit