Looking for someone to identify an addon that I had back when Nostalrius was up. I then deleted the whole game along with addons when it shut down. The addon displayed health/mana on your party, pet, target and yourself. You could also use /commands to decide wether it showed the health or mana on mouseover only or wether it showed it all the time.
So you could have it show health of your party and pet only on mouseover, and then have it show the health of your target all the time. I'm adding here a video that I recorded back then for another use, you can see on it how it looked like.
I'm not sure if it used mobhealth/mobinfo or if it was actually a version of them. I've yet to find a version that would actually have all these commands. Hoping someone would be able to identify it!
https://www.youtube.com/watch?v=_kahGBqR4fU