I would recommend using Discover cards on cdkeys.com. Why Discover cards? Don't hate on the little guys. They are really beneficial if you know how to use them correctly. Discover are good because unlike visa, they dont have much security and are easy to get successful transactions. Why don't you just use discover cards for normal carding? I would say they are ideal for giftcards because they are usually low balance (<500) so I would card steam giftcards (20$) as many as u can until it declines.
On Newegg.com (ideal for US) card ebay 200$ giftcards and sell them on paxful in exchange for bitcoin (cc to btc).