The death of all the gems' guardians are suitably epic, though the triumph over Reeah stands out as particularly Badass, with Jasmine cutting the giant snake's throat with Lief's sword, killing it with grace and coolness while saving his life.
Hell even Kree got got to be badass, being the one to defeat Theagan.
The scene where Lief figures out the proper order of the gems at the last minute.
That scene is awesome in both the book and in the Anime. In the Anime, he invades the palace, rescues the resistance, and uses everyone's knowledge to outsmart the Grey Guards and in the Ols. In the book, he as no such help. he breaks in alone, by way of a secret tunnel, sneaks past everyone in the palace, climbs up, and figures out the gems right before he puts his plan into action.
What Glock does right before he dies.
Lindal's entrance in Dragon's Nest.
Doom is pretty much a walking example of this trope.
Jarred and Anna both. They cheerfully got up and walked away from their entire lives to go and live in what was, to them, Nightmare Fuel Forest. Anna in particular is an unsung hero of the series, because she spends the entire time dead. Endon and Sharn are pretty incredible in what they pulled off too.
When Kree managed what no one else could, killing Thaegan. It's pretty poetic that she be defeated by a creature she'd only ever thought of as a tasty meal.
Jasmine and Doom's match during the Rithmere Games, in the anime. Loved Jasmine kicking Dooms smarmy ass.
In the anime adaptation, Lief nearly falls from a tower, the bird once known as the "Enigmatic Giant" returns out of nowhere and saves him, paying back his life debt.
I know most people are Prin haters but, I loved watching her take down the Vraal.
Prin: "Green is the good moss, it takes away the pain. Purple is the bad moss, it brings it back again."