backlog

cache, fund, hoard, inventory, kitty, nest egg, reserve, stock, stockpile, store, supply

accretion, accumulation, assemblage, collection, cumulation, cumulus, gathering, lodgment (or lodgement), pileup

agglomerate, assortment, congeries, conglomerate, conglomeration, hodgepodge, hotchpotch, jumble, medley, mélange, mishmash, mix, mixture, motley, potpourri

agglomeration, clutter, hash, heap, litter, mass, pile

aggregate, aggregation, sum, totality