Hi Natascia. I used to shoot with a Nikon D600, the precursor to your camera, and I frequently used the Yongnuo 560iii speedlights with it (and Yongnuo RF-603 triggers when I wanted to use them off camera, which is how I most often shoot). They work great--still do, in fact. I use them with my D810 and have had them for going on three years now. I know many photographers who use Yongnuo.
It looks like Yongnuo has updated their speedlights--the YN-560iv appears to have the trigger built in, which is nice! I haven't used this updated version, so I can't say how they work in comparison to the old 560iii version nor how effective the built-in trigger is.
Here is the older version I still use:
https://www.bhphotov...arch=yes&sts=ps
If you want to use it off camera, you will need a set of triggers:
https://www.bhphotov...less_flash.html
And here is a link to the new, updated 560 iv with the built-in trigger:
https://www.amazon.c...ongnuo yn560 iv
If you are planning on using the camera exclusively on camera, you don't need the triggers anyway. (But I hope you are planning on going off camera--much nicer light.)