Liquid cooling grabs all the headlines, but the true cooling ideal is passive cooling. That means a bunch of heat fins and nothing else. No moving parts, no messy fluids to pump around, no additional power sources to pipe in. Just a lot of fins.
Of course, like most high-end computing hardware, this becomes a physics problem. To adequately cool your GPU with fins alone, you need a GPU that wasn't too hot in the first place. Thankfully, Nvidia has delivered this year with the GeForce GTX 1050 Ti, the low-ish end of its 10XX lineup.
Now a company called Palit Microsystems has surrounded a 1050 Ti card in a "vast volume" of nickel plated fins and shipped one of the first perfectly silent cards of this generation. If you're building a tiny PC you might balk at the bulk all these fins add. Also, remember you'll need to get the heat these fins are dissipating out of your PC case at some point before your RAM and CPU become a puddle. If you do have any other fans whirring in your PC, a few slow-spinning fans on your 1050 wouldn't be your noise problem in the first place. But if your goal is a perfectly silent computer, Palit's 1050 Ti KalmX card is a good first step.
No word on price or a ship date for the card, but it's already on review benches so it can't be far off.