all GF and Player cards are unique (also there is but one unique boss card...PuPu) but there is something to remember (whilst this is entirely up to you on if you do it) the items gained from refining player and gf cards are very hard to get (disc 3 high level item refining or rare item ability required) and can be very useful for raising powerful gf's. Now I haven't played FF8 in a long while but back when I did I had every card and the clock was frozen (though the memory card clock read well over 500 hours) I had every item and was considered either (a) Insane or (b) one of the most useful walking FF8 guides around here. I believe that there is a way to regain such cards if modded for items on disc 4 (queen of cards her rules such a pain to do.) However I cannot personally remember if it is merely the cards gained in the QoC quest or all said unique cards available in game. My honest advice is if you don't mind playing for extra time and going up to level 100 with all your chars then don't mod especially for hyper wrists (not the best item to come from card modding neither is the samantha souls gained from the Quistis card) and wait untill disc 3 to gain the items from fights and modding items.

Any further questions like where to get player cards and gf then just pm me. Hope I help