The calamity salvager does if you've completed the event in the past. Other than that, the cash shop is the only place to get them if you missed out, though there used to be an event vendor npc that sold them in game before the cash shop was put up but unfortunately that npc is no longer placed in game for the event. If it's not on the shop yet, it most probably will be when the event rolls back around. If it's a special event though, no one really knows when or if those are going to be obtainable again or how, if at all.