Emma Frost, formerly known as the White Queen, hasn't been a member of the X-Men all that long compared to the likes of Cyclops, Jean Grey, or even Wolverine. For much of the team's history, Emma was an antagonist as the White Queen of the Hellfire Club. She first came onto the scene to interfere with the X-Men's recruitment of the young Kitty Pryde.
However, Emma has been a consistent member of the X-Men since she first joined. She has stuck with the team through several crises, and currently enjoys a position on the Quiet Council of Krakoa and heads the Hellfire Trading Company, which helps supply much of the finances for the sovereign mutant nation
10 Trying To Save Magma
One of Emma Frost's first significantly selfless acts was attempting to save the New Mutant along with Magneto and the rest of the Inner Circle of the Hellfire Club. On a prolonged journey back home to Italy, Magma was captured by the mutant-hating religious extremists, the Purifiers.
The Hellion Empath contacted Emma about this crisis, and she contacted Magneto, then leading the New Mutants on behalf of Xavier, and the Hellfire Inner Circle to save Magma from the Purifiers. The irony is that the New Mutants had already saved Magma from the Purifiers, and this selfless act was unnecessary.
9 Saving The New Mutants From Sabretooth And Ousting Shaw
However, Emma would later help Magneto save the New Mutants from a different sort of threat. Sabretooth, then working as a Marauder under Mister Sinister, was at the site of the then-destroyed X-Mansion, and attacked the New Mutants. Magneto and the Inner Circle of the Hellfire Club battled Sabretooth.
The Inner Circle came to blows with the New Mutants shortly after, but Magneto defused the fight. However, Sebastian Shaw wasn't happy with Magneto's presence in the Hellfire Club, and Shaw tried to usurp Erik. Magneto won the struggle, and Shaw was ousted from the Hellfire Club. Emma wasn't sad to see him go in the slightest.
8 Taking Down Shaw With Namor
This wasn't the only time that Emma Frost worked to see Sebastian Shaw humbled. During Norman Osborn's Dark Reign, Emma Frost was implanted into Osborn's Cabal to represent mutant-kind in this malevolent group, which also included Taskmaster, Loki, the Hood, and Namor the Sub-Mariner. Emma and Namor made a pact shortly after joining, as they had a romantic history together.
Namor wanted Sebastian Shaw dead, and Emma offered to help make this happen so long as Namor accept his identity as a mutant and work towards their benefit. Emma helped take Shaw down but spared his life. She used her telepathic abilities to make Namor believe Shaw was dead and then locked him away in a prison controlled by the X-Men.
7 Appointing Kate Pryde As Red Queen
Kitty/Kate Pryde had a grudge against Emma Frost since she first tried to recruit the young mutant into the Hellfire Club. Emma did little to help resolve this, even after she joined the X-Men. However, with the establishment of the Hellfire Trading Company on Krakoa, Emma needed to appoint a Red Queen to run this side of things alongside herself and Sebastian Shaw.
To this end, she chose Kate Pryde, as she knew she would challenge Emma as needed. This unfortunately resulted in the apparent death of Kate at the hands of Sebastian and Shinobi Shaw, and Emma mourned Kate dearly and has worked tirelessly to see the Five bring her back to the realm of the living.
6 Saving Scott From Himself
Shortly after the big move to San Francisco, Emma detected that Scott's mind was beginning to fray. To repair this, she personally went into Scott's head to discover what was bringing Cyclops to the brink.
While Emma and Scott share a romantic relationship, and this could be interpreted as a semi-selfish act on behalf of Emma, she still worked to make sure that mutant-kind had a stable and mentally-healthy leader at that dire time.
5 Giving Xavier New Purpose
After being away from his X-Men for some time, Charles Xavier returned at one point to warn Cyclops about the return of Mister Sinister. Scott was still angry with Xavier for his many mistakes and manipulations, and Emma had reasons of her own to dislike the Professor.
However, instead of trying to do him harm, Emma used Charles' own memories to find a new purpose in his life instead of clinging to the X-Men, which had moved beyond him at that point. Obviously, this didn't stick, but it was still a kindness for Charles at the time.
4 Rallying The Mutants To San Francisco
After the enactment of the Superhero Registration Act, the X-Men were offered a haven in San Francisco, as California wasn't enforcing the SHRA.
Cyclops and Emma Frost went to San Francisco, and the latter pushed her telepathic abilities to its limits to summon every mutant she could reach to seek safety with the X-Men in California.
3 Taking On The Skrull Psychics
When the Skrulls invaded Earth during their Secret Invasion, Emma and the Stepford Cuckoos took the fight to the Skrull telepaths aiding their species in the planetary takeover.
Even after the Cuckoos dropped out of the fight, Emma continued to fight against the Skrull psychic force on her own.
2 Sacrificing Herself To The Phoenix Force
During one of the Phoenix's many returns to Earth, it targeted Cyclops to use his powers to empower itself. The X-Men devised a plan, and it involved Emma Frost allowing the Pheonix Force to take her over for a time.
Given the history of the Phoenix and what it did to Jean Grey, this was an immensely selfless act on behalf of the former White Queen. In the end, the returned Jean Grey saved Emma from the Phoenix before the X-Men could dispatch the entity.
1 Betraying Norman Osborn
Going back to Dark Reign, Emma Frost played a daring coup against Norman Osborn, his Dark Avengers, and his Dark X-Men. Dark Beast (of the Age of Apocalypse Earth), Daken, Weapon Omega, Namor, and Mimic were recruited by Osborn to be part of the Dark X-Men team with Emma Frost.
However, Emma always worked for the benefit of the X-Men and, along with Mindee Cuckoo and X-Force, openly betrayed Norman Osborn to free mutants that the Dark X-Men had been capturing.