Earth-188888

Earth-188888 also called Ultron M is an alternate universe to the Marvel Cinematic Universe with several alterations, akin to Earth-12.

Timeline
The events before Avengers: Age of Ultron are the same, expect the existence of mutants and events that came after.

Good

 * Tony Stark / Iron Man
 * Steve Rogers / Captain America
 * Dr. Bruce Banner / The Hulk
 * Thor
 * Agent Natasha Romanoff / Black Widow
 * Agent Clint Barton / Hawkeye
 * Director Nick Fury
 * Director Phil Coulson
 * Agent Maria Hill
 * Sharon Carter / Agent 13
 * Agent Melinda May
 * Agent Leo Fitz
 * Agent Jemma Simmons
 * Skye
 * Agent Peggy Carter
 * Howard Stark
 * Virginia "Pepper" Potts
 * Col. James Rhodes / War Machine / Iron Patriot
 * Samuel Wilson / The Falcon
 * Corporal Timothy "Dum-Dum" Dugan
 * Dr. Betty Ross
 * Dr. Erik Selvig
 * Jane Foster

Neutral

 * General Thaddeus "Thunderbolt" Ross / Red Hulk
 * Capt. Emil Blonsky / The Abomination
 * Mike Peterson / Deathlok

Bad

 * Obadiah Stane / Iron Monger
 * Justin Hammer
 * Ivan Vanko / Whiplash
 * Loki
 * Johann Schmidt / Red Skull
 * Dr. Arnim Zola
 * Alexander Pierce
 * Sgt. James "Bucky" Barnes / Winter Soldier
 * Baron Wolfgang von Strucker
 * The Clairvoyant / Agent John Garrett
 * Agent Grant Ward
 * Raina
 * Ian Quinn
 * Thanos
 * Aldrich Killian
 * Malekith

Teams

 * X-Men
 * The Avengers
 * Howling Commandos
 * Warriors Three
 * Thunderbolts
 * Brotherhood of Mutants
 * S.T.R.I.K.E.

Good

 * S.H.I.E.L.D.
 * Stark Industries
 * Strategic Scientific Reserve (SSR)

Neutral

 * U.S. Military
 * World Security Council
 * The Rising Tide

Bad

 * Hammer Advanced Weapons Systems
 * Hydra
 * Project Centipede
 * A.I.M.
 * Norse Paganist Hate Group