1 level of regen in the army now is such that I don't foresee any situation where I would reinforce anything other than Skeletons and Grave Guard.
I could see reinforcing zombies. if they survive a round of combat you can get some healing in which means more chances to proc mortals when they do die, and a bigger unit when they respawn after death.
I know zombies are super dowgraded from what they were, but I've often looked at the obr crematorian subfaction and said "this ability would be amazing on some cheap trash unit like zombies", and here we are. so not as good as they were, and they no longer benefit from offensive buffs like they used to so it's harder to build around them. but I could definitely see a couple units of 40 thrown in to an army that uses monster heroes & vampire units as their main offensive pieces.
I also feel like a lot of people are underrating neferata? between the redeploy, the speed, the passive aura, the spell, on a double caster w/ decent attack and great self healing, she's very good.
LoBlood, w/ nef, VLoZD, a couple units of blood knights, and like 3x40 zombies might be something? maybe?