Although Nvidia doesn't have anything in way of replacements for its last-generation mid-range cards, it will do in the future and so it's looking to shift stock of the Pascal generation to help make way for those new cards in the market -- and offer a competitive package to AMD's RX 500-series with their bundled games too. The title Nvidia has chosen to help shift its cards is the exceedingly popular and well-received, Monster Hunter: World, which will be free with select GTX 1060, 1070, and 1070 Ti graphics cards starting today.
The promotion is called, "The Hunt Begins," and will run until November 29 at select retailers all over the world. Although not an envelope-pushing game in terms of artwork, Monster Hunter: World is by far the prettiest entry in the series as of yet and with a few tweaks and the right settings, any of these cards will be able to make its environments and monsters look gorgeous.
It can be a little hard hitting on hardware though. A GTX 1060 is likely to be able to get around 60 FPS on medium-high settings, but expect some dips into the mid-40s if your CPU is weak or during the most frantic of hunting moments. A GTX 1070 or 1070 Ti will be much more capable and should be able to output 60 FPS at high settings at 1440P.
Monster Hunter: World doesn't benefit massively from 4K, but we'd recommend the 1070 Ti or even something higher if you want to go for that.
For full details on the promotion, check out Nvidia's page. You can find a list of supporting retailers there too, should you wish to buy from somewhere specific.