Usually, if you go with AMD, then the processor that they release will go well with the previous year graphics card and the same year graphics card that the new processor releases. For example, the Ryzen 5 1600, 1600x, 2600 and 2600x go well with a RX 580 and RX 590.
As far as Nvidia mixed with AMD, I am not too entirely sure. I know that the 1060 and 1660 will be nice with the Ryzen 5 1600-2600x, since the 1060 and 1660 are both equivalents to the RX 590. But Intel? No idea as I do not wish to ever use them.