Earth-101

Earth-84260 is an alternate reality within the Marvel multiverse in which the Avengers witness a horrific future where Thanos possesses the Infinity Gauntlet and rules over the entire galaxy, but worse yet, the planet Earth has been destroyed. Still possessing a fighting chance in the present, the Avengers must work together with any other heroes they can find to change the future.

Prophecies of the Future
The Prophecies of the Future are the events discovered by Thor during his brief stay in the future. It is theorized that if enough of the events can be changed, the horrific future will not come to pass.
 * Ultron Betrays the Avengers
 * In the future, it is revealed that Ultron, the Avengers' AI robot designed for peace on Earth overrides his programming and attempts to wipe out all of humanity. Getting ahead of the curve on this one, the Avengers dismantle Ultron completely before he has the chance to betray him. But this only sped up his inevitable betrayal, as he is able to download his consciousness into the internet and begin amassing power before he is disabled.
 * Stark Industries Goes Bankrupt, Bought Out by Oscorp
 *  To Be Revealed...
 * The Power Stone is Misused by AIM and Destroys a Small Town in Nevada
 * To Be Revealed...
 * The United States of America and Latveria Declare War Against Each Other
 * To Be Revealed...
 * The Death of Spider-Man
 * To Be Revealed...
 * Atlantis Joins the United Nations
 * To Be Revealed...
 * Hulk Goes on a Rampage in Asia, Accidentally Kills 9 Civilians
 * To Be Revealed...
 * Wakanda Recovers the Power Stone, Is Besieged by the Black Order
 * To Be Revealed...
 * The Sentinel Program is Reinstated Following Magneto's Expansion of Genosha
 * To Be Revealed...
 * Hydra Perfects the Super-Soldier Serum, Begins Amassing Army
 * To Be Revealed...
 * Galactus Devours Skrullos, Resulting in a Secret Invasion of Earth
 * To Be Revealed...
 * The Venom Symbiote Bonds to Cull Obsidian
 * To be Revealed...
 * The Kree Empire Authorizes the Termination of All Inhumans
 * To Be Revealed...
 * The Invisible Woman Dies in Childbirth
 * To Be Revealed...
 * Asgard Closes Off Communication with the Nine Realms
 * To Be Revealed...
 * Human Torch Barricades Himself in the Negative Zone to Stop Annihilus from Invading
 * To Be Revealed...
 * Jean Grey Comes Into Possession of the Mind Stone, Unleashing the Phoenix Force
 * To Be Revealed...
 * Thanos Sacrifices Gamora, Obtaining the Soul Stone
 * To Be Revealed...
 * Doctor Strange Disappears, Leaves the Time Stone Unprotected
 * To Be Revealed...
 * Thanos Obtains the Infinity Gauntlet, Destroys Planet Earth, Conquering the Galaxy
 * To Be Revealed...

Avengers

 * Steve Rogers / Captain America
 * Tony Stark / Iron Man
 * Thor Odinson
 * Carol Danvers / Captain Marvel
 * Bruce Banner / Hulk
 * Natasha Romanoff / Black Widow
 * Clint Barton / Hawkeye
 * T'Challa / Black Panther
 * Janet van Dyne / Wasp
 * Scott Lang / Ant-Man
 * Sam Wilson / Falcon
 * James Rhodes / War Machine
 * Pietro Lehnsherr / Quicksilver
 * Wanda Lehnsherr / Scarlet Witch
 * Vision

Fantastic Four

 * Reed Richards / Mister Fantastic
 * Susan Storm-Richards / Invisible Woman
 * Johnny Storm / Human Torch
 * Ben Grimm / Thing

X-Men

 * Professor Charles Xavier
 * Jean Grey / Phoenix
 * Scott Summers / Cyclops
 * Alex Summers / Havok
 * James "Logan" Howlett / Wolverine
 * Hank McCoy / Beast
 * Ororo Munroe / Storm
 * Warren Worthington III / Angel
 * Bobby Drake / Iceman
 * Kitty Pryde / Shadowcat
 * Kurt Wagner / Nightcrawler
 * Marian Carlyle / Rogue
 * Remy LeBeau / Gambit
 * Piotr Rasputin / Colossus
 * Illyana Rasputin / Magik
 * Betsy Braddock / Psylocke
 * Laura Kinney / X-23
 * Jean-Paul Beaubier / Northstar
 * Alistair Silvercloud / Forge

Heroes for Hire

 * Luke Cage
 * Danny Rand / Iron Fist
 * Jessica Jones
 * Felicia Hardy / Black Cat
 * Roberto da Costa / Sunspot

Inhuman Royal Family

 * Blackagar Boltagon / Black Bolt
 * Medusalith Amaquelin / Medusa
 * Crystalia Amaquelin / Crystal
 * Triton
 * Karnak
 * The Reader
 * Lockjaw

Independent Heroes

 * Peter Parker / Spider-Man
 * Doctor Stephen Strange
 * Namor McKenzie / The Sub-Mariner
 * Matt Murdock / Daredevil
 * Wade Wilson / Deadpool
 * Robbie Reyes / Ghost Rider
 * Eric Brooks / Blade
 * Frank Castle / Punisher

Hydra

 * Johann Schmidt / Red Skull
 * Ophelia Sarkissian / Madame Viper
 * Baron Helmut Zemo
 * James "Bucky" Barnes / Winter Soldier
 * Arnim Zola
 * Wilson Fisk / Kingpin

Brotherhood of Mutants

 * Erik Lehnsherr / Magneto
 * Raven Darkholme / Mystique
 * Victor Creed / Sabretooth
 * Morty Tolensky / Toad
 * Emma Frost
 * Jonathan St. Allerdyce / Pyro
 * Fred Dukes / Blob
 * John Proudstar / Thunderbird
 * Jason Wyngarde / Mastermind
 * Neena Thurman / Domino
 * Dominic Petros / Avalanche
 * Irene Adler / Destiny
 * James Madrox / Multiple Man
 * Tabitha Smith / Bombshell
 * Arkady Rossovich / Omega Red

Sinister Six

 * Otto Octavius / Doctor Octopus
 * Max Dillon / Electro
 * Mac Gargan / Scorpion
 * Quentin Beck / Mysterio
 * William Baker / Sandman
 * Aleksei Sytsevich / Rhino

Independent Villains

 * Doctor Victor von Doom
 * Nathaniel Richards / Kang the Conqueror
 * Ultron
 * Norman Osborn / Green Goblin
 * Eddie Brock / Venom
 * Cletus Kasady / Carnage
 * Cain Marko / Juggernaut

The Infinity Stones

 * Space Stone
 * Mind Stone
 * Time Stone
 * Power Stone
 * Reality Stone
 * Soul Stone

The Black Order

 * Thanos
 * Hela
 * Nebula
 * Ebony Maw
 * Corvus Glaive
 * Proxima Midnight
 * Cull Obsidian
 * Loki Laufeyson
 * Ronan the Accuser

Asgardians

 * Odin Borson
 * Freyja
 * Thor Odinson
 * Loki Laufeyson
 * Brunnhilde / Valkyrie
 * Heimdall
 * Fandral
 * Hogun
 * Volstagg
 * Lady Sif

Guardians of the Galaxy

 * Peter Quill / Star-Lord
 * Gamora
 * Drax the Destroyer
 * Subject 89P13 / Rocket
 * Groot
 * Mantis
 * Kamaria / Moondragon
 * Phyla-Vell
 * Beta Ray Bill
 * Adam Warlock

Kree Empire

 * Supreme Intelligence
 * Ronan the Accuser
 * Mar-Vell
 * Phyla-Vell
 * Noh-Varr
 * Yon-Rogg
 * Minn-Erva
 * Korath the Pursuer

Skrull Empire

 * Queen Veranke
 * Dorrek VII
 * Talos
 * Kl'rt / Super-Skrull
 * Anelle
 * Titannus
 * De'Lila
 * Pitt'o Nili

Independent Players

 * Galactus
 * Norrin Radd / Silver Surfer
 * Sam Alexander / Nova
 * Annihilus
 * Uatu the Watcher