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. 4-01 : LC - Facebeater's big stick smashaz
Ref. 4-02 : DW - Good timing
Ref. 4-03 : SD - Fandelhoch's hellblaster
Ref. 4-04 : SM - Grimjaw's personal bodyguard
Ref. 4-05 : WA/HW-Grimjaw's undying slayers
Ref. 4-06 : WA/BD - Grunson's marauders
Ref. 4-07 : SD - Haargoth
Ref. 4-08 : HD/WA - Ha'asek, The Archon of Twilight
Ref. 4-09 : LC - Ironfist's disciples
Ref. 4-10 : BR - Iyar, Lord of Tzeentch