HumaniTale: Takes place in the underground, in a universe where the monsters won the war. They need seven monster souls to leave. The characters aren't human versions of undertale characters, but rather completely different people who simply look and act like the human versions. Monster kid and Frisk switch places. Chara and Asriel switch places.

Stuff for it:
*(You tap Chara's shoulder.)
*Hey.
*What are you doing?
*Go away.
*I'm going to turn back into a plant again. It isn't any use.
*...
*Fine.
*I'll just ask an uncomfortable question.
*Why the hell, all puns intended, did you climb this mountain?
*... Well, I guess the fact that you don't speak much... Kinda... Interferes with the uncomfortable question plan...
*Well I guess it's for only you to know anyhow. I can respect that.
*I mean, Asriel never told me, and, yknow...
*But all anyone needs to know about that is that it wasn't for a happy reason.
*...Asriel hates monsters. Im partially responsible for that. You see, I once managed to crawl out of this mountain. But I got hurt by a monster on the way back in.
*I guess that, combined by, well, whatever he faced on the surface, just turned into this boiling anger and stuff.
*...Yknow....
*I wasn't the best person at times. Or a good sibling...
*He would've loved you, Frisk.

--

CursedTale

CursedTale-- Everyone is half monster, half human.

A long time ago, there were two classes. Those of strong souls, and those of weak. The strong were rich and powerful, and the weak were poor, weak, servants, peasants, and slaves. However, the weak souled had a special ability. They could use the souls of the strong to become even stronger than the higher-ups. The strong feared a rebellion, where this would happen, and started a war. Millions of weak were killed in the process, but not a single strong soul died. They banished the innocent weakers to a remote place, hidden by a wall. And to add insult to injury, they cursed their former servants, turning them into twisted beings that were half human and half complete monster.

Legend says, if you find the wall, Wall Ebbott, you won't come back.

Undyne- Mermaid
Alphys- Dragonnewt
Dreemurrs- Saytrs
Muffet- Arachlady
Papyrus+Sans- Zombies
Mettaton- Cyborg
Blooky- Ghoul

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TragedyTale
It's an AU where all the characters are humans, with normal names, and Undertale itself is actually just a story. The catch, though, is that undertale is a story written by 'Frisk' as a tribute to their dead friends and families, who died in ways that live on in the book.

'Undyne', was 'Frisk's' aunt, and died trying to save an indie singer from drowning(Shyren).
'Alphys', their other aunt, accidentally caused for lots of people to die from lethal medicine and was given her sentence privately; the electric chair. Undyne wasn't alerted that her girlfriend was going to die that day, or that she was gonna die at all. She was going to receive a note on the evening of the execution, after it took place. That day also happened to be the day she drowned, so she never learned that her fiance was dead.

'Mettaton' suffered a horrible accident that almost left him dead. He got surgery and prosthetics, and was fine for a while. He resumed his life as a star, and got even more famous, assuming the role as someone for amputees to look up to. But then the prosthetics malfunctioned...

'Toriel' and 'Asgore' were Frisk's adopted mother and father, and were diplomats. They went on a trip, ran into trouble with terrorists, and got trapped separately in two crumbling structures and left to starve. Toriel actually helped six children escape the structure she was trapped in, though.

'Sans', 'Frisk's' stepfather, and 'Papyrus', their stepuncle, were policemen. The difference was that 'Papyrus' was still in training under 'Undyne', while Sans was full fledged. They were both killed by a serial killer called Player, who claimed a demon made them do it, and that it wasn't their fault, even as they looked someone in the eyes and killed them.
'Chara' and 'Asriel' were 'Frisk's' siblings. 'Chara' absolutely hated everyone outside of family, because of their past before being adopted. They died of accidental poisoning, and died holding 'Asriel' in their arms and trying to reassure their best friend that it was okay, and to not be such a crybaby. Asriel committed suicide shortly afterwards, too shaken by their sibling's death to ever be okay.
Chara first inspired the Undertale books. After their death, Frisk dedicated their life to making sure their memory lived on. And then dedicated their life to make everyone else live on.