Cade Skywalker's rejection of Darth Krayt's temptations not because he chooses the Light Side, but because power doesn't interest him.
Darth Krayt sitting upon the throne of the Emperor. By himself, Krayt has restored the galaxy to the Dark Times.
Topped when he comes back from the dead. Then he tops that by echoing Palpatine when he says that everything is preceding as he planned.
Darth Wyrrlock gives a Shut Up, Hannibal! to Darth Andeddu and then promptly slaughters him in a Dark Side duel, proving the One Sith are just as powerful as those who followed the Rule of Two.
Cade in issue #19 when he, after only about two months of Jedi/Sith training following seven years of disuse, takes on Krayt, Talon, and Nhil- and he defeats the Hands in seconds before battling Krayt to a standstill, all the while refusing the call of the Dark Side.
The Heroic Sacrifice of Captain Yorub when he kamikaze attacks the Mon Calamari shipyards and destroys a third of them, preventing the Sith Empire from creating anymore ships there.
Kol taking down around 10-20 Sith by himself by being struck down my Nihl to save Jedi younglings.
Cade resisting Muur's influence and shattering his talisman with Force energy while Muur can only scream in impotent rage. After watching Muur torture Celeste for 8 issues, seeing Cade banish the guy into oblivion as well as Muur's Villainous Breakdown was quite satisfying.
One for Krayt on Korriban close to the beginning of the series. After contacting the spirits of three Sith Lords (Bane, Nihilus, and Andeddu), they denounce him as a "pretender" due to uprooting the Rule of Two that Bane created, then use the Force to accelerate the growth of the Yuuzhan Vong organisms that are slowly killing Krayt. Cue him them spraying the organisms with Force Lightning to make them recede before denouncing the Lords around him, saying that if they won't help him, he'll find his own way.