NHF – new heroes for Heroes V 3.1.

Well, many standard Necropolis heroes already have their own unique appearance... Kaspar, Ravenna, Deidra...

I used heroes from the campaigns of Heroes of Might and Magic VII (for example, Lyudmila, a favorite, although I haven't played Heroes of Might and Magic VII, she's beautiful)):)

Added after 59 seconds
But there's Tamika (portrait, model of Lucretia)

Added after 1 minute
And Kaspar exists (he's called Lord Fendragost, but he's a story character).