A continuation of this reference post that I did a while back. It seemed to get a good response from the public, so why not add this as a bit of an extra?
These are references compiled from a couple different websites. I’ll link below a handful of tutorials that may also be helpful in designing memorable or unique characters (or perhaps even more helpful in spicing up already-existing designs). All from Deviantart; most of them go over generally the same thing, but they each have a few little tidbits that are really useful/interesting/inspiring.
Tutorial: Character Design by ky-nim
Character Design Tutorial by Miss-Dutch
Character Design Tutorial? by Mademoiselle-Nuit
Character Design Tutorial by MarionetteDolly
Unique Character Design Tips by thundercake
Facial Structure Tutorial by DayDawnDusk
Character Design Tutorial by Narsilion
My Approach to Character Design by WonHitWonder
Mini-tutorial: Facial Diversity by FOERVRAEGD
Unique Features Tutorial: Pt 1 by jeinu (and its other two parts-not linked)