When Commander Sullamander introduced a tyrannical new law forbidding sexual relations between stallions and mares, a new Chief of Staff named General Wind Whistler rallied the other Chiefs to her side. She then showed Sullamander a passage in the Articles of Command (the Celestine Junta's version of the Constitution) stating that she was a traitor to the Junta, and gave her thirty seconds to renounce her treason, or suffer a painful and humiliating death.
The Final Battle of the Celestine Civil War (Wind Whistler's coup against Sullamander), ended with a fight between Sullamander, Hurricane, and Pansy. While details about it are sparse (there was only one witness, who missed most of it, and Hurricane and Pansy never talked about it afterwards), we do know how it ended — Pansy, while beaten, bloody and half-crippled, still managed to stab Sullamander twice with throwing daggers, and stared her down as she tried to kill her in retaliation. At which point Hurricane ran a sword through Sullamander from behind, finally killing her.
When the corrupt Unicorn court attempted a coup by murdering the entire royal family, the last remaining prince fled to Star-Swirl for help. Star-Swirl responded by traveling to the court and completely wiping the floor with every single noble there (reports vary, but some say there were as many as 600 ponies present).
After Hearth's Warming, Princess Platnium — realizing that her court will never accept peace with the other tribes — has them all killed. Even in-universe, this is considered a Kick the Son of a Bitch moment.
Just about all of Commander Hurricane's life qualifies. Think about it: he suffers greatly in his youth for being born the wrong gender in a strictly matriarchal society. So how does he deal with it? By playing down his stallionhood? All the contrary. He is basically what testosterone would be like, if testosterone were a pony.
The Lake Trot Crisis has a few to go around:
Cripps, the Republic force leader, using hardened pastries and bum rush tactics to confuse and curbstomp the Unicorn forces.
What is argueably even more impressive is the fact that they not only held the line against, but even forced into retreat, the forces of the Celestine Junta, the best military force in the valley. And they did all this with only one casualty... Via choking on a sandwich.
Meanwhile, a Pegasus unit known as the Burning Timber Wolves uses a massive tornado to do its own share of damage; this unit eventually evolved into the famous Wonderbolts.
How did the Warming come about? Well, when Hurricane found out about Pansy's affair with Trencher, he kicked off the Winter War just to find him and kill him. Pansy, still recovering from her pregnancy and carrying her son with her, mind you, knocked out the guards keeping her under house arrest. Then she tracked down her father and fought him to a standstill until forcing him to accept her love for Trencher and stand down. Which, ultimately, was the final trigger for the Warming and the extinction of the Windigos.
The Congressional Convention to form a unified Equestrian government nearly turned into a battle between the pro-democracy and pro-stratocracy factions, until Hurricane arrived at the scene, fully decked in battle armor and accompanied by all the still-living mares who had served as his Chiefs-Of-Staff over the years (some twenty-odd of them), pulled aside the stratocracy faction's leader (one of his daughters)... and talked her down, getting her to accept democracy. To repeat: A guy who spent his life as a warrior resolved a situation peacefully, which is about 20% More Awesome.
Hurricane: I did not put down the Junta just to see it rise again.
Even better, it's implied in one of Smart Cookie's letters to her husband that he was only supporting democracy in order to impress Clover. Guy knows how to go all out.
Platinum's Thanatos Gambit, the final act in a lifetime of magnificence — by killing herself, she not only ends the royal line, but causes all the royal family's money and holdings to default to the Equestrian government, keeping them out of the hooves of the nobility. This finally completes Platinum's long-term goal of breaking the nobility's back, eliminating their last chance of ever regaining their stranglehold on the common pony. Hell, at the very least, this ruined Count Pyrite's plan to force her to (or forge documents to make it look like she did) make Clover's adoption by the royal family official so that he could then make Clover's son the new Puppet King (and knowing Platinum, she already knew all about this scheme).
Even better: Clover's son had no intention of ever becoming king anyway.
Speaking of Pyrite, when he's ranting and cursing Platinum's name for daring to die before he could use her, his son Musco and Musco's secret Pegasus lover Whirlwind (both of whom despised the Count for his narrow mindedness, racism, and generally unpleasant nature) kill him and then dump his body in a compost heap to rot.
The Battle of the Corridor: Star Burst leads what's left of the Equestrian military in holding the line against Talonhoof's horde in order to buy time for refugees to escape. One highlight is Star Burst, in his eighties, personally fighting Talonhoof himself, who's thirty years younger than him, and nearly killing him twice.