This website supports the ability to play a superset of Dungeons & Dragons using card game mechanics in place of magic and spells.
The site has a filterable list of all of the cards currently avaliable in the playable set.
The collection page that allows you to collect and use cards from your campaign. Card collections are stored locally in your browser so you don't have to worry about losing that rare card between sessions!
As a DM you don't need to worry about having to list off specific card collections NPC shopkeepers have in stock, they are recorded in autogenerated shopkeeper pages.