Taylor's utter casual annihilation of the Slaughterhouse Nine. A group so feared that they constitute an S-class threat on their own, and she slaughters them with such ease that she can taunt them.
She almost single-handedly ends an alien invasion. Though not before enjoying the comparatively more mundane sensation of being in space for the first time.
Taylor cripples the entire Borg Collective by driving half the drones to rebel ... by singing Do You Hear the People Sing to Locutus (and, through him, the rest of the Collective).
Props to the Borg as well, they don't take it lying down. While Taylor manages to cause damage to the Cube with the Saratoga's weaponry, she notes it starts repairing quickly. When she releases her own nanobots to cripple the ones repairing the Cube, the Borg nanites fight them at every turn until finally managing to subsume the foreign nanobots (and trigger an automatic self-destruct feature to prevent them from gaining their superior technology). When Taylor sings to Locutus (which Taylor notes can't be interrupted for a moment less the Collective reassert control of the rebels), the Borg first flood the room with gas, then vent the atmosphere entirely, then try teleporting her away (which her power reads as attempted disintegration). Finally, the Collective cuts its losses and just cuts the Cube's connection to the rest of the Collective.
Taylor kills Leviathan. How? After fighting him and taking advantage of her new Escalation power to gain strength and increase all her skill levels, she teleports to another star with Leviathan, rips its tail and bites into its core, killing the monster - and improving her water control powers to the point that she could probably control all the water on Earth at the same time.
During this fight, Loki saves a lot of lives by using his illusion magic to hide everybody else from Leviathan's water-sensing power.
Taylor only needs five minutes to completely screw up the Master's plan by teleporting to the Valiant, No Selling everything he tries to throw at her and introducing him to both someone that has no qualms at destroying him physically (which she does) and that can hear the drums that he has been hearing his entire life. Then, after the Doctor recovers his health, she destroys the Paradox Machine, heals the TARDIS (gaining enough levels to Blink that she can now jump 120,000 light-years!) and then saves the Master from being killed - potentially preventing Rassilon's plot. Oh, and she also becomes a proto-Time Lady!
Fred Rogers was chosen to be an Indigo Lantern. The rings usually chose criminals who have 'no' compassion, and only very rarely do they choose those who embody it.
Taylor singlehandedly orchestrates the overthrow of Tynanda's dictatorship without anyone the wiser, and despite her self-recrimination, the cost in innocent lives is a lot lower than had the rebels had to do so unaidedly.
She utterly destroys Thanos' plans by virtue of having lost the Mind Stone in another universe. Then proceeds to flatten him in combat then wiping out his entire force, after pulling herself out of a black hole.
She tears apart Sentry, a superhuman whose powers grant him whatever ability he needs to win, not by trading him blow for blow, because she knew she'd lose if she tried - but by tearing him down as a person. Due to how his powers work, she literally manages to depower him by digging into all of his insecurities, flaws and failures and forcing him to confront them.
When she needs a meatshield to keep from getting instantly pulped until her Escalation catches up? She grabs Juggernaut and puts him between her and the mentally unstable Superman pastiche.
Taylor doesn't fight Behemoth. Calling it a fight would imply the fight wasn't utterly one-sided. Taylor not only manhandles the Herokiller, she treats it as a joke and uses him as a training dummy, focusing more on gaining resistances out of him than killing him. Behemoth ends up trying to run away from her, but then she takes it to Mars and starts punching it harder and harder using Behemoth's Attack Reflector power to improve her resistances, and only stops when she accidentally destroys Mars by punching too hard. That's when she decides to stop playing around and tears Behemoth apart like tissue paper, gaining its absolute control of energy and another level of worship empowerment.
She then stays on Mars and mentally does all the calculations to keep the planet together and prevent its transformation into an asteroid belt that could end up affecting Earth.
All of Taylor's plans are up in flames when Samael (the entity behind Silent Hill) manages to get from its home to Earth Bet through the Simurgh, tricking Scion into believing Eden is there. Cue the Final Battle, as Taylor lifts all the stops and fights everything Samael throws at her, while the many heroes she's met in her travels pull off The Cavalry by coming in and helping Taylor deal with the multiversal threats. And as Samael pushes its power through other universes to twist people, Loki reappears with the Mind Stone and connects the minds of all of humanity from all the parallels to Taylor, allowing her to use music to give everyone the courage to stand against the tide.
While the battle takes place, we are shown the point of view of a Earth Bet New Yorker trying to escape from some of Samael's creatures that are attacking the city. He nearly falls to its manipulations when the song begins. Cue everyone - gangbangers, normal people, policemen, everyone - coming up and taking the fight to the monsters.
In another place, an eighty year old man (appropiately called Moses) guides a group of those unable to fight towards a safe place. Fred Rogers appears to them, giving them the hope to find their way - and cue in Amazing Freaking Grace, with everyone singing it to keep Samael at bay, before Moses goes out to keep helping people.
