Pixel-Me, a pixel art character portrait generator, is now on sale at half price at Itch.io:
https://tassilo.itch.io/pixelme
The Random button is a quick way to produce NPC portraits in one click. Randomization does not change the color palette. Single elements can be locked or shuffled...
Another Steam Weekly deal - Portrait Wizard for 25% off:
https://store.steampowered.com/app/685300/Portrait_Wizard/
It's worth noting that this is Early Access software.
The character generator for an upcoming CRPG Spire of Sorcery could be useful for a TTRPG GM as well, IMHO:
https://store.steampowered.com/app/893560/Spire_of_Sorcery__Character_Generator/