Unfortunately, you are unlikely to find trusted gift card sellers, I have never met a legitimate seller or service.
Professional carders immediately sell gift cards to proven cashing services for 70-80% of the balance or buy cryptocurrency or goods in online stores with them, that is, none of the reliable guys will sell you gift cards for 10-50% of the balance, it just doesn't make any sense or profit.
E-Gift cards from balances for 30-50% of the cost are sold only by impudent scammers on full prepayment. You will never receive gift cards or they will give you data that turns out to be invalid.
But there is a way out if you want to get gift cards - this is to learn how to do carding yourself or to hire novice guys from the "Job" section, but you need to provide them with material - non vbv cc, and the sites on which you want them to try to buy gift cards.
But you must understand that they may not succeed, since for each site you need to know the correct non vbv bins, which can only be earned in the process of work and you are unlikely to find such good bins in the public.
Please consider this circumstance.