Your best shot is to try eBay or find a seller on instagram or something like that. I don’t think they will be cheap though, probably around 80-100 a deck from what I’ve seen lately.
Hey! Well the first reply pretty much summed it up. I’ve helped a few people find the core Monarch set, and found Silver pretty fast. I don’t know how many were printed, but iirc it was one of the core colors. That’s probably why.
Where have you looked? Feel free to DM me if you’d like some more info.