I found a set of cables online for my Corsair AX850 power supply. I added another GPU last night and found that I needed one more 6-pin PCIe connector; my 1080 only needs one (and I only have two right now, enough for most people) whereas the old 670 requires two. No problem - I found a complete set on FleaBay.
<cue record scratching sound effect> Wait - what?
Yeah, no thanks. That might be worth it if I needed all of the cables, but I think I can find just what I need a little cheaper. And I don’t have a problem not using every port on my power supply and using adapters to get the connections I need - it’s a working computer, not a showpiece full of RGB stuff. I’m happiest when I can neither hear nor see my computer.