The TTArtisans 11mm f/2.8 fisheye lens is now available also for Nikon Z-mount cameras. The lens is already available for sale on eBay and AliExpress for $219-$255 (Amazon should also get them soon):
The Z-mount version is not yet listed at ttartisan.com, but I got a confirmation that this lens does exist.
Additional information (MTF charts, specs, lens design) and sample photos from the M-mount version of this lens can be found here:
The new TTArtisans 11mm f/2.8 fisheye lens for Leica M-mount
