Synonyms to ace in the hole

advantage, backlog, bulge, cache, coign of vantage, drop, edge, flying start, head start, inside track, jump, nest egg, odds, reserve, reserve fund, reserve supply, reserves, reservoir, resource, running start, savings, sinking fund, something extra, something in reserve, start, stockpile, unexpended balance, upper hand, vantage, vantage ground, vantage point, whip hand