Since some of you have your doubts that this thing can really power a graphics card from a SATA power cable, I've taken a closer look into how a PSU supplies power and what this adapters limits really are.
New link (as of 1/24/2021) to adapter (6 or 8 pin):
https://www.ebay.com/itm/173610565849
The link usually goes dead so if it does let me know and I'll try to update it. You can also search "sata male to 8pin" on ebay and usually find it with relative ease. You may notice the cable in the link is a dual sata to 6 or 8 pin. I've started only recommending this because it lets your gpu draw power from two sata cables which is safer. However I wouldn't say this is the best method or the safest, so try at your own risk.