Series from the Multiverse.

[boltmonster]

What alternate reality from the Marvel Multiverse wound you like to see as a series?

[SuperiorIronman]

A good What If? (it also got reprinted awhile back) was Doctor Doom becoming a hero. He was essentially a hero without much of the baggage that made Doom questionable to others. It would be a fun world to explore seeing as while he has the same motivations as 616 Victor, he's effectively more noble. And to that end, how would the world be changed if a Victor existed who was more inclined to join the FF and Avengers rather than fight them? That's a whole line that could come out of that considering Victor has a hand in a ton of heroes an villain's histories.

And outright if we keep the heroic theme; the Lang's don't die, Battleworld plays out differently, potentially the Future Foundation might have Doom instead of Spider-man given Victor would be on better terms here. Victor wouldn't go to war with Wakanda and might very well sit Dark Reign out. That also brings us to Infamous Iron man, where Victor may be Iron man with Tony's blessing rather than Victor stepping in out of altruism that Tony doesn't believe.

There's some stuff their I'd like to see explored.

[mugiwara]

The Spider-Man Life Story reality. Or at least something working the same way.
Not only a series, but a whole set of series, like the Ultimate Universe, where super heroes aged in real time.

[Kaijudo]

This is a bit of a cheat because it's become part of the Marvel Universe proper, but my favorite What If was the one with the 1950s Avengers (Marvel Boy, 3D Man, Gorilla-Man, Venus, Human Robot). Though most of those characters eventually became the original Agents of Atlas, I'd love to see the continuing adventures of those characters in the 1950s, with their original outfits/backstories.

[Huntsman Spider]

As an ongoing? Bring back Technopolis, the Battleworld domain featured in the Armor Wars mini from Secret Wars 2015. Heroes, villains, and civilians alike in Stark-issue armor as the only solution to a virus that has permeated the atmosphere and would otherwise kill them all. The actual plot, though, is kicked off by the mysterious murder of the vigilante Spyder-Man, which leads to the discovery of some dark truths behind the world of Technopolis and how it came to be. I'd love to see his story and adventures pre-death fleshed out more.

[616MarvelYear is LeapYear]

What is a multiverse, how does it work, and why does it matter?

[strathcona]

I'd like to see a new Exiles series, one that incorporates characters and ideas from all the previous runs and have them hoping around time and space again.

But if I had to choose one specific reality, then it would be the original Squadron Supreme universe. I'd love to see more of it's history explored, find out where and how it diverged from the 616 (or at least from 616like realities]. Though, I'd want to see all the alternate Squadrons removed from the 616 also.

[CaptCleghorn]

The Spider-Man Life Story reality. Or at least something working the same way.
Not only a series, but a whole set of series, like the Ultimate Universe, where super heroes aged in real time.

I'm going to second this. There was an FF Annual where they had aged in real time and we saw older characters and extended families. This would be a great Universe to work with for some stories.