The next two Nikkor Z mirrorless lenses to be announced are:
I do not have an exact date yet, but there is a possibility that both lenses could be announced together with the D6 or shortly after (the D6 is expected in the first half of February). Stay tuned for additional info.
The latest Nikkor Z lens roadmap can be found here:
Additional pictures of the upcoming Nikkor Z 20mm f/1.8 S lens: