Western Animation: Legion of Super-Heroes aka: Legion Of Superheroes
The Animated Adaptation of the Legion of Super-Heroes comic book series. Ran for two seasons, 2006-2008, abruptly ending with a hook for the third season that never came.When the series opens, the 31st-century Legion is hopelessly outclassed by the famed Fatal Five. They resolve to recruit the near-mythical Superman from the past, but for undisclosed reasons, Brainiac 5 brings them to Smallville, not Metropolis. There they invite 18-year-old Clark Kent to help them in The Future, promising that with Time Travel, he can return the minute he left.At Brainy's insistence, everyone studiously avoids telling Clark who he's supposed to become in the future. Regardless, Clark finds the Superman Museum, connects the dots, and takes the costume from the display case, and the name of Superman, for his own. Together they defeat the Five, and then Adventures Happen.The show had a very Silver Age tone to it, but the most noticeable and controversial change from the source material was turning team genius Brainiac 5 from a Human Alien into an android. Word Of God is that this was supposed to tie him more closely to his ancestor the original Brainiac, as well as avoiding having to explain how an an organic can be the 'descendant' of a robot, clearing away a fifty-year-old example of Writing Around Trademarks.Season two saw everyone age about two years, even Brainy, and the show went Darker and Edgier after the very light and bouncy first season. The premiere visited a Bad Future where Superman's clone was bred to fight Galactic Conqueror Imperiex, who when cornered escapes back to the 31st century and proceeds to wreak havoc as the season's Big Bad.The character sheet can be found here.
Not to mention Brainy and his obsession with Superman... which, thanks to the opening of season 2's first episode may be a whoooole lot less ambiguous.
Big Eater: Bouncing Boy eats every bit of food he can reach because the fat guy always eats everything in sight. (In the comics, he's fat only as a side-effect of his powers, and doesn't have any more of an appetite than any other person.)
Book Ends: For both seasons; moreso in the second.
Chekhov's Skill: Superman X's Kryptonite immunity. It was mentioned only once, when introducing himself and how his LEGO Genetics make him stronger, however, it never saw any use in the series proper until the finale, where it saves the Original Superman's life.
Civvie Spandex: A bizarre variation. The costumes the superheroes themselves wear are perfectly in keeping with superhero tradition, but the dress of the non-super characters and background characters suggest that this trope may somewhat be the case.
Combining Mecha: Hoo boy. In the season two finale: the towering fusion of every Coluan ever, with Brainiac's Skull Ship as the head.
Composite Character: In "Phantoms," Drax is based on a hodgepodge of Phantom Zone criminals, is implied to be the son of General Zod and Faora/Ursa, and has many design elements of the non-Kryptonian Zod from Superman: Birthright.
Custom Uniform: Most of the characters' uniforms follow the pattern of a three-part division with a center band of contrast running down the middle, and all of them have the Legion emblem somewhere on their waist.
Evilutionary Biologist: Dr. Londo, Timber Wolf's father. He's the reason why his son looks the way he is and it's strongly implied that he wasn't the only victim of his genetic experiments.
Foreshadowing: Superman X's cryptic message to Brainiac 5 at the season 2 premiere. This will be followed by Brainiac's last words from the end of "Who Am I?": "But that would mean the potential for evil is also within...all of us." Of course, finally there's "Message in a Bottle".
Fun with Acronyms: although it doesn't spell out a word, and it's more like a Mythology Gag: the so-called "Heroes for Hire" Light Speed Vanguard, which will later be known as the Legion of Super Villains.
Future Imperfect: A lot of details were apparently lost in "the great Crisis". Meaning, among other things, no one remembers the Phantom Zone's name or that it even exists.
Kid Appeal Character: As a contrast with the other, much darker elements that accompanied the new season, a young Chameleon Boy joins the Legion in the Time Skip.
Laser-Guided Amnesia: The reason every adaptation brings Saturn Girl to Smallville. But by season two, in a creepy Shoot the Dog moment to protect the timestream, Brainiac 5 uses a memory-flasher on Superman. Which, in light of the rest of the episode and combined with the self-satisfied look in his eyes is another nail in the foreshadowing coffin that the more ruthless Brainiac 1.0 had infected his mind and would turn up later.
Mecha-Mooks: Imperiex's army, which he somehow still has after arriving in the past, are unfortunately named "Destructo-bots" at one point. Before that, Brainiac 5 all but served as a renewable Red Shirt, since robot injuries get a free pass from the Media Watchdog, especially one who can self-repair.
Merchandise Driven: Probably why the Legion ship got unceremoniously blown to smithereens in the second season premiere, only for a replacement to arrive within seconds.
Pet the Dog: "Unnatural Alliances" for both Superman X and Imperiex. Although, the latter had no choice, seeing as his existence actually depended on it. Followed by a Kick the Dog immediately afterwards.
Stable Time Loop: Superman only becomes Superman because he finds out he's going to be Superman, and learns heroism from a team that was inspired by his own future heroism, so...
Time Skip: Season 2 takes place two years after the end of season 1.
Token Minority Couple: Fangirls who were not that familiar with the comic tended to ship Dream Girl and Cosmic Boy together in fan fiction because they didn't see any other options.
Took a Level in Badass: Season 2: the intro theme, and the main characters' appearances (possibly justified by them aging along with the audience). Lightning Lad now has a soul patch, for example.
Brainiac 5: Do not worry. Soon this agony shall pass, as it will pass from this entire universe. Once my work is complete, there will be no more pain, no more chaos. Only a perfect order imposed by me.
What the Hell, Hero?: at least twice, between Brainiac and Superman, with the latter calling Brainy out for hiding both Supes's weakness to a red sun in "Brain Drain" and the original Brainiac's involvement in the shrinking of Kandor in "Message in a Bottle". And also when Brainiac suggested risking the Kandorians lives with Imperiex.
With the former, Brainiac 5 told Superman he apparently failed to un-shrink Kandor.
White-Haired Pretty Girl: Triplicate Girl, one-third of the time — white with colored streaks, in her combined form (it changed in season 2)
Duo Damsel: Terra-Man, word is you've been terrorizing this entire prairie in search of someone. Star Boy: The only thing you're gonna find here is trouble. Bouncing Boy: With a capital "L"!