First off, I'm a leftie too, and it aint a curse, but a gift, showing our capacity to adapt and prevail in a world designed by the inferior right-handed majority
Joke's aside, it depends on the type of holster you're looking for.
Belt mounted, MOLLE, drop leg ? hardshell or soft ?
You could go the Blackhawk Serpa way like I did (for my M9), and you also have these :
https://www.sealsactiongear.com/cata...?idProduct=578 Uncle Mike universal molle
https://www.sealsactiongear.com/cata...?idProduct=539 Seals 4.0 special ops
Hope this helps.