There’s a lot of gift cards on sale right now in the Daily Deals section of eBay. Sadly these deals are not as good as they used to be without eBay Bucks and portal cash back. Still you can get a decent discount on some merchant plus whatever miles/points/cash back you get from your credit card.
There’s a few $100 gas gift card that have a 7% discount such as BP, Sunoco, Speedway, Philips 66 and Conoco. There’s also $220 Southwest gift cards on sale for $200, sold by PPDG and that means an extra 5x with your Ink cards.
There’s other discounts too, but watch out for preowned gift cards. Better steer clear of those.