I have D7200, I am shooting with Sigma 18-35mm f/1.8 DC HSM Art. The pictures which are coming from this lens are superb. Super sharp even wide open, it really took me by surprise how good it is. At 35mm you have equivalent of 50mm FF. It is a bit heavy lens, around 810 g. A bit more expensive, but the build/image quality is totaly worth it.
Another one would be Tamron SP 17-50mm f/2,8 XR Di II VC. It is much cheaper, build quality is a bit less. Not as sharp wide open, but you have more range. At f8 it is as sharp as the Sigma.
I am sure if you look these up, you will find a lot of sample pictures and reviews.
If you need more range. Than the Sigma 50-100mm f/1,8 Art is super sharp. Same series as 18-35, a bit more expensive and the range is not the biggest. But for portraits it is all you need.
It mainly depens on you budget, but I have to say, Sigma 18-35 is just perfect for me. Bokeh would be better on some primes of APS-C 50mm+. But even the sigma at 35mm can do some nice bokeh shots, I am sure you can find some on flick Sigma 18-35 group.
Here is a shot (nothing great, just some plant shot at f1.8. iso 280), as you can see it is sharp wide open and even some small bokeh.