This mod is not currently maintained; you can find an updated version here: https://www.curseforge.com/minecraft/mc-mods/npc-variety-port

This mod requires the Fabric API: https://minecraft.curseforge.com/projects/fabric

This mod gives has the following features for villagers and illagers alike:

8 skin tones, ranging from white to black, with vanilla villagers around the middle. The majority of NPCs in a given biome will have realistic skin tone range appropriate for the climate, with some exceptions.
5 eye colors. Green (vanilla), blue, light blue, brown, and amber. Ravagers also have these eye colors too.
Close their eyes while sleeping. Currently only villagers actually do sleep, but if the others ever sleep for some reason (like another mod) their eyes will close as well.

Villagers pass on these traits to their children. Next up, zombie villagers also have 8 skin tones (but their eyes are still all red), and converting back and forth they will retain all their features.

Illagers spawn 5% of the time (15% for pillagers) with an eye patch on either eye, and all of them can have 16 different colored trousers at random.

- Planned features

Color variations for villagers clothes as well.
More head features (like the eyepatches) will be added for both.
Something with witches.
Skin tone variations to ravagers as well when I can get the textures right.
Random blinking for all of them.

NPC Variety