Over the years I have been commissioned to both make custom resin masks for customer, and also made masks in bulk myself to sell to many enthused customers.
Most of these masks are out of production now, their moulds having served for many years. Though if one does take your fancy you can likely either ask directly to see if the mould is still serviceable or request a new sculpt custom only to you.
Some of these masks, namely the Reaper and Roadhog masks have been replicated tens of times over multiple years. With the Reaper mask showing up in a surprising video production after being purchased from myself over Etsy by an adult actor or his production crew.