This is the base mesh I use for some of my works,

Inner mouth, teeth and eyes included.

I hope it will help you through the realization of any character you wish to create.

This model has been made in Blender v2.9 and forward compatibility is guaranteed up to the latest stable release.
Blender v2.8x is not supported, although a swift test has been made on 2.83 and everything appears to be working correctly.

MODEL:
Character made completely from scratch
19'024 Tris
Clean Topology
UV Unwrapped
Rigged (V 1.1)
Everything in the outliner has been clearly named

FILE FORMAT:
.Blend .FBX .OBJ

UPDATE V 1.1:

Completely Rigged with Rigify (Mouth and Eyes included)