Heads from Skyrim.

Regarding textures, there are textures that their authors created from scratch. Regarding the face model: 1) I'm not sure, but it seems like RaceMenu has added content for individual parts of the head, such as lips/nose, etc. 2) You can definitely add these parts with certain mods and/or completely replace these models (replacement is a fairly popular category of mods for faces, as they are quite rough in the original, of course). 3) At the same time, in RaceMenu itself, you can take some kind of ready-made face and completely rework its vertices using the "Sculptor." That is, you can create a face that doesn't borrow anything from anywhere, even if it's not created from scratch. In terms of models, not in terms of textures, and I'm not considering various small details like eyelashes, and you can't rework things like crystals in this way, and some other things. In fact, the interface of the sculptor is clearly visible in the first screenshot in this topic.