I'll spitball a guess your way.  The value of D&D collectibles has gone up lately overall with certain items like original D&D woodgrain and white box sets and shrink wrapped items increasing the most.  Inflation is likely a factor. Critical Role is perhaps a factor, among other things.  Therefore, I wouldn't doubt that your card set has increased in value from even two years back.  However, as those card sets were not widely used and/or pursued in years past, the likelihood of a significant increase is unlikely.

I don't mean to be snarky, but the value is whatever someone will pay for it.  If you want to sell it, you'll get the highest price from eBay.  No one else comes close to offering you the biggest audience of potential buyers.  Yes, they take a percentage.  Yes, eBay has its issues.  Still, my opinion is that it's the best way to sell if you want the biggest profit.  If you need to sell it quick, offer it in an auction.  If you don't need to sell it quick, offer it with a Buy-It-Now price that you suspect is too high, like maybe $500.00, and see if you have any takers for a month or two.  Then slowly lower the price until it sells.  If you want a wild guess as to what I suspect it'll sell for, I'll say $250, maybe $300.  

Congrats on the achievement!

If you do decide to part with the collection, let us know in the Classifieds.