With the new Nikon Z 70-200mm f/2.8 VR S announcement, the current Nikkor Z mirrorless lens lineup consists of 11 differenmt lenses:
The latest Nikkor Z lens roadmap includes another dozen of not-yet-announced lenses for a total of 23 Z lenses by 2021. You can see the shapes of some of the upcoming lenses on this new poster Nikon had on display at their CES booth (credit: Napolean_Chan @Weibo):
Here is another angle of the same poster:
Next are a few size comparisons done by a reader (thanks drororomon):
Check out also all the third party lenses for Z-mount.
Pre-order the latest Nikon products here