I happen to find these Secret cards in my Futurecard Buddyfight stash. Perhaps you are looking for some of them, check them out below.
Card Name: Retainer of the Demonic Dragon, Jovnozak
Status: Near Mint, Played
Set: D-CBT/0127EN SECRET
Price: $6.00
Stock: 4
Card Name: Bearer of Sins, Batzz
Status: Near Mint, Played
Set: X-BT01A-CP01/0071EN SECRET
Price: $5.00
Stock: 1
Card Name: Great Demonic End Dragon, Azi Dahaka
Status: Near Mint, Played
Set: D-BT03/0115EN SECRET
Price: $6.00
Stock: 4
Card Name: Retainer of the Demonic Dragon, Fernyiges
Status: Near Mint, Played
Set: D-BT03/0116EN SECRET
Price: $5.00
Stock: 4
Card Name: Spawn of the Demonic Dragon, Haarid
Status: Near Mint, Played
Set: D-CBT/0126EN SECRET
Price: $6.00
Stock: 4
Card Name: Black Sky Sun Dragon, Azi Dahaka “Daeva”
Status: Near Mint, Played
Set: D-CBT/0123EN SECRET
Price: $6.00
Stock: 4
Card Name: Demonic Dragon Deity of the Black Sun, Gaen
Status: Near Mint, Played
Set: X-BT01/0124EN SECRET
Price: $7.00
Stock: 2
Card Name: Terminus Dragon Emperor, Endervelt
Status: Near Mint, Played
Set: X-BT01/0125EN SECRET
Price: $6.00
Stock: 5
Card Name: Dragon Drei
Status: Near Mint, Played
Set: X-BT01/0128EN SECRET
Price: $3.00
Stock: 2
Card Name: Retainer of the Demonic Dragon, Walm
Status: Near Mint, Played
Set: X-BT01/0127EN SECRET
Price: $5.00
Stock: 3
Card Name: Retainer of the Demonic Dragon, Horned Serpent
Status: Near Mint, Played
Set: D-CBT/0128EN SECRET
Price: $6.00
Stock: 1
Card Name: Retainer of the Demonic Dragon, Devil Orb Dragon
Status: Near Mint, Played
Set: X-BT01/0126EN SECRET
Price: $5.00
Stock: 3
Card Name: Demonic Demise Sword, Aqulta Gwaneff
Status: Near Mint, Played
Set: H-BT01/0104EN SECRET
Price: $4.00
Stock: 1
Card Name: Demonic Demise Dragon, Azi Dahaka
Status: Near Mint, Played
Set: H-BT01/0101EN SECRET
Price: $5.00
Stock: 2
Feel free to send private message to my Facebook Page, LJGaming, if you want to purchase these cards or have some inquiries.