Heads from Skyrim.

If I don't forget, I'll write later how to fix the square shadows on the face in Maua6.

By the way, yes, it would be interesting to read about this later.

Added 3 minutes ago

At the same time, in RaceMenu itself, you can take some kind of conditionally ready face and completely rework its vertices using the "Sculptor". That is, you get a face that, although not created from scratch, does not borrow anything from anywhere.

It still borrows. It's still the same model, just the vertices have been moved. It's still the same mesh, the same UV map.

Added 10 minutes ago
I googled a bit and didn't find any face models created from scratch for Skyrim. Maybe they exist, but I didn't come across them.

There's only this disaster:

When a guy just throws a turbo-smooth modifier on top of the model, and voila, it's now ultra-mega-super-next-gen-high-poly.
The load on the computer increases by two times for no reason, and there is no difference in the game. Don't do that. Models are not raster images. More polygons do not equal better quality.

Wow. That wasn't the limit. It can be even higher poly.


Added 15 minutes ago
And here's a wonder for Oblivion.




The author writes something like:
All head model and texture assets are my own work based on Bethesda meshes and may be used as modders' resources. Original hairstyles included in this mod also apply.

Perhaps he still used Oblivion models as a reference, but judging by the appearance, there is a new mesh and textures. You can compare and check.
In any case, it seems that the author gives permission to use his work in mods.

Here's the link if you need it.
Just if you use it, mention who the author is and where you got it from.

Added 9 minutes ago
There's a mod with new face models and textures for M&M Warband, but it only has female faces. This mod is an OSP, i.e., its resources are free to use, provided that the author is credited.

Download link