NVIDIA is quickly making good on its promise to support its latest graphics cards on Macs. The GPU giant has quietly posted beta macOS drivers (direct download) that should support any GeForce 10-series card, whether it's a simple GTX 1050 or an all-out beast like the Titan Xp. It's a big step forward for Mac users who've had to settle for 9-series cards at best. However, the big challenge will be making the most of the cards given the current Mac lineup -- this is as much an investment in the future as anything.
Right now, this makes the most sense if you have a previous-generation Mac Pro and are either a gamer (not the biggest segment of Mac users, we know) or run media creation apps that can take advantage of NVIDIA's added computing power. Otherwise, you're looking at decidedly unofficial solutions, such as external Thunderbolt graphics enclosures (which do appear to work) or "Hackintosh" systems using off-the-shelf PC parts.
While there's nothing official, you could see this as laying groundwork for the Mac Pro relaunch, which could come as soon as 2018. Even if Apple has no intention of shipping NVIDIA graphics with the new desktops, this should give you more choice for video cards if the stock options don't cut it.