There is a bunch of alien CC mods but you can’t create a unique sim without alien skin tones. So, if you’re looking for non-human skin colors, this is the perfect mod to get. This alien skin overlays set published at mintyowls.tumblr.com is another answer if you were looking for more variety for content related to aliens! Head over to this site for more information about this content for The Sims 4. Further skin overlay cc and mods are listed here!