I presume the OP means these ones:Which wallpaper? I see it is using the Mojave wallpaper when it mentions Mojave. I was able to see the desktop in a different picture and it was using the High Sierra default wallpaper. I am not seeing other wallpapers in screen shots.
I presume the OP means these ones:
I'd be interested too if anyone could find them.
Apparently notAh thanks for clarifying as to what to look for! I wonder if they are included in Mojave. I do not have the beta or I would check