When I own a card, its Gold number and the quantity I own are indicated.
If the quantity (the second number, after the "x") is greater than 1, then the card is available for trade.
I'm looking in priority for cards I don't own at all, whatever Gold value on the back. But I'm willing to get also cards I already have but with a different Gold value.
Also, all cards don't have the same back, but it's not my priority to get all cards with all backs!
For the differents backs, see
Ref. 5-02 : BR - Lillet Nightwind
Ref. 5-01 : WA/SD - Izzumbard Endrinkuli
Ref. 5-03 : SD - Malekith's black host
Ref. 5-04 : SD - Numerical Advantage
Ref. 5-05 : DW - Strategic planning
Ref. 5-07 : LC/SM - Rein Volkhard
Ref. 5-08 : HW/WA Theodoric Gausser, Guardian of the Empire
Ref. 5-09 : SD - Rhyian Dawnrider
Ref. 5-10 : BR - Stoneheart's Doomseekers