As Excalibur once found out during the Cross-Time Caper, a journey through numerous alternate realities, none of the team’s counterparts included a version of Rachel, leading to the assumption that she was a person who had very few if any analogues across the multiverse. This was essentially proven correct in Uncanny X-Men #462 when Rachel visited the White-Hot Room, a nexus to all realities. Whereas her teammate Psylocke saw numerous
In a different version of the “Day of Future Past” scenario, shown in Fantastic Four (1st series) #414, Rachel Summers was not transported back in time, and her lover, Franklin Richards survived. Eventually they were married, and had a child named Jonathan Reed Richards. Unfortunately, he was too powerful, went mad and called himself Hyperstorm, threatening the entire multiverse. Blaming his parents and effectively his paternal grandparents for how super-powered beings had been treated in the timeline, Hyperstorm time-traveled to the present with a vengeance in order to make the Fantastic Four pay. He was nearly successful, though in the end Mr. Fantastic lured him into a trap, locking Hyperstorm, empowered by an unlimited power source, into a seemingly endless battle with Galactus, the cosmic devourer with an infinite hunger. As he never reappeared afterwards, Hyperstorm might have died in the conflict.
In another reality, depicted in [Exiles #12-13, 59], Rachel and Franklin too had off-spring, a redheaded boy they named David. By the time he was six years old, his parents and most other superbeings had been killed by the Sentinels, and David lived in a concentration camp. Eventually, he would have grown up to become a near omnipotent, cruel leader, which is when the dimension-hopping Exiles and their rival team Weapon X came in. Actually, their job was to kill the boy to prevent the millions of human deaths he would cause, but they found a better solution by Sabretooth staying behind and ensuring that David would experience a normal childhood. Unfortunately, Sabretooth failed and, two decades later, he had to kill David nonetheless when he went on a mad rampage.
During another mission to an alternate reality, the Exiles even met one Rachel Summers in person, as was shown in [Exiles #21-22]. Her Earth had been almost entirely overcome by techno-organic beings. Rachel (non-Phoenix, but still powerful) was one of the few surviving, non-infected heroes. When Morph noted the absence of Asgardians in that world, he asked Rachel to telepathically contact the Asgardian gods across the dimensional barriers. The gamble worked and indeed were the Norse Gods of great help, for their blood contained a certain regenerative factor from which a serum could be derived to reverse the effects of the techno-organic infection, thus saving humanity on that Earth.
Ten to fifteen years in the future, the re-appearance of Jean Grey heralded the End of the X-Men. Though it occurred in deep space, Rachel sensed her mother’s rebirth on Earth. Still, she abandoned her job as manager of Kitty Pryde’s campaign to become Mayor of Chicago only after a series of attacks on the X-Men and their friends.
Rejoining the X-Men, Rachel helped her brother, Cable to beat an infection with nano-robots before traveling to Shi’ar space to face the mastermind behind the recent attacks, Cassandra Nova. Against all odds, Cassandra managed to beat Jean and wrest control over the Phoenix Force from her, and Rachel too found herself overpowered when she tried to claim the Force. Rachel later joined several others in creating the “Tree of Life” from the Quabala and presumably transcended this plane of existence.
In the altered reality of the House of M, Rachel Grey was the bodyguard and traveling companion to Lady Elisabeth Gloriana, alias Psylocke, British royalty after her brother Brian became ruler of all England. Having recently returned from adventuring abroad, Rachel and Betsy became involved in Captain Britain's mission to seal the rift in causality created by the Scarlet Witch's manipulations that created this twisted reality in the first place, to prevent its chaos from spreading to other universes.