Well, the Vargheist figures are still available from
GW for their Age of Sigmar game (as part of the Flesh Eater Court faction,
IIRC).
If you don't want to go that route, Reaper Miniatures makes some demon figures that you could use.
03771: Shadow Demon
03747: Bat Demon
03063: Gargoyle
I don't have exact sizes, but based on prices these are all larger-than-28mm-human sized.