In an issue of the original continuity, a half-dozen other legionaries are convinced they've been poisoned and are dying. Karate Kid, the Legion's sole member without proper super powers, decides he wants to go out with a bang instead of a whimper and heads out to take on the entire Fatal Five, a group that has stood up to the entire Legion before, all by himself. He wins. Damnit!
Then there's how Karate Kid gained admittance to the Legion—by picking a fist fight with the insanely powerful Silver Age Superboy and lasting a few minutes. Or the time he tore apart solid titanium gates in order to break his fellow Legionnaires out of prison. Or hell, the fact that, when superpowers were briefly outlawed, Karate Kid was banned from using his martial arts skills, because they were so advanced as to qualify as a power.
Projectra has a classic one after Nemesis Kid kills her husband, Karate Kid. It really needs to be seenfirsthand.
From "The Legionnaire Who Killed": Superboy, Mon-El, Ultraboy, and Supergirl, all of them invulnerable, coming to Starboy's defense when the Legion puts him on trial for killing a man in self-defense. Superboy's argument manages to sway almost half the Legion to his side, and only loses the case by a couple of votes, despite the fact that this was the Silver Age when a superhero killing somebody was pretty much verboten.
Shrinking Violet telling off her decidedly ex-boyfriend, Duplicate Boy of Lallor, for not doing anything to save her when he realized she'd been switched with Yera... and then having the gall to still think they were a couple.
Lightning Lord attacks Lightning Lad and Saturn Girl, Garth trying to hold back as they're fighting in a med-center. When Lord calls Saturn Girl "a telepathic slut," Garth's eyes glow solid yellow energy. "Mekt...you just made me forget you're my brother." The next panel shows Lightning Lord being blasted through three walls.
R.J. Brande, the Legion's patron and financier, has a moment as awesome as anything the Legion did. In "Superboy and the LSH" #258, he confronts the man who stole his fortune and made the richest man in the galaxy a pauper ... the President of the United Planets! At a full, public council meeting the President admits it, starts to cry, and explains why he did it — to finance the reconstruction of Earth after a recent devastating war. He knew otherwise there'd be years of poverty, starvation, etc. He finishes ranting "and I'd do it again!" And is led off a broken man. A councilwoman addresses Brande and reassures him there will be restitution. And Brande tells them no. They can keep the money, because although it was illegal, what the President did was absolutely right. And he marches out of the council chamber, saying "I made one fortune, I can make another. And by God, we'll BOTH be rich again". Cue thunderous applause.
Tenzil Kem is appointed Brek Bannin's legal defense after Brek had been jailed for two years pending trial, for holding a "pep rally in a pizza party". After going through multiple shenanigans, from surprise witnesses to having Brek dress up in bizarre costumes to have him declared unfit for trial, the judge orders that any attempt to dispute Brek's sanity is a fraud. As Tenzil is trying to think of what to do, the judge then informs Tenzil he is prolonging Brek's so-called speedy trial. Tenzil then points out Brek was withheld a speedy trial for two years. The judge counters that the two years were necessary to prove Brek's competence to stand trial. Which, of course, the judge had just ordered that any attempt to disprove Brek's competence is a self-evident fraud. The judge is left stammering as the prosecutor lets Brek go free.
The three founders of the Legion of Super-Heroes, in the Legionnaires Annual #2, standing down the Ax-Crazy Kryptonian-level members of the White Triangle after the rest of the Legion has been defeated:
Saturn Girl: We were the first three. We're going to be the last three, aren't we? Cosmic Boy: Maybe. Probably. I'm sorry, guys. Saturn Girl: For what? For giving us a chance to be heroes? Don't apologize.
Shortly previous, Karate Kid, the Legion's resident Badass Normal, takes on one of the White Triangle Daxamites, giving him a rude awakening from his A God Am I power trip by kicking him in the head. When a shrapnel wound in the thigh from the spaceship the Daxamite dropped leaves him unable to stand, Karate Kid fearlessly invites the Daxamite to come within reach so he can continue beating him up.
Chameleon and Infectious Lass in Gail Simone's "For No Better Reason" arc:
Arrow:[weakly] I'm... I'm willing to die for my cause. Chameleon: Oh, you'll die. We'll all die someday. The issue is, do you want to die in bed, surrounded by your loved ones... or bent over in this alley with a woefully inadequate supply of tissues?
Duel CMOA here, Superboy puts his hand on Pulsar Stargrave's shoulder and Stargrave with one punch puts Superboy in orbit. Before Pulsar can complete his next sentence, "Now Legion..." Superboy is back, and he's mad. He b* &ch-slaps one of Pulsar's toadies...and promptly gets blasted with red-sun radiation. But it was a nice moment while it lasted.
There was that one time Matter-Eater Lad saved the entire Legion, including Superboy, by eating his way out of an underground prison. Walls, dirt, and all.
Heck, ME Lad once saved the whole galaxy. Brainiac 5 had gone crazy and used the Miracle Machine to create Omega, an undefeatable embodiment of all the hatred in the universe. ME Lad stopped it by...eating the Miracle Machine.
Mon-El, the single most powerful Legionnaire after Superman left the team, saved all of creation with a Heroic Sacrifice when he changed the universe by punching time. Take that, Emoboy-Prime!
The Ranzz Family, Garth, Imra, and Ayla, rescuing Garth and Imra's twin boys, Graym and Garridan, from a cult that worships Darkseid on the planet Avalon. The finishing touch was Imra utterly DESTROYING the cult leader with a projection of Darkseid in his mind, speaking as a woman with experience in having dealt with the dark god beforehand.