Hi, two of them were sold in the market place ( Zorathian Cosmotheque+Ba'li Arches) and one was obtained by participating in a site event (Flux). In the present none are available, so you have to wait for future sales or events to get them.

There are no cards on the site only artifacts, those displayed as cards are listed under your achievements and have no effect and cannot equip or dispose of them.

Any artifact you've missed you'll probably never get, at least not for a long time.