A Crown of Stars: The pendulum swung hard back and forth here. “A Throne of Bayonets” -the previous story- was as cynical as it gets. The After the End world was a nightmarish place inhabited by starving masses scavenging the ruins and ruled by blood-thirsty dictators. Shinji and Asuka were turned into war tools and Asuka was two dictators' sex slave for three years. Although they finally met again and were determined to stick together they were so burn-out than having a real relationship seemed impossible. The present story is fairly idealistic, though: Shinji and Asuka meet a powerful ally who is determined to set things right for them. They finally have help, start to repair their relationship, and prepare to other war, this time with a cause is actually worth fighting for, an army at their back and gods on their side.
Advice and Trust: This story explores what could have happened changing a single event of the Eva canon. The result so far is a more idealistic story where the main characters learn to communicate and face their troubles together rather being unable to understand each other and falling apart due to loneliness, lack of communication and hurt.
Last Child of Krypton: Shinji believes wholeheartedly that everybody have some good in them, a person can change fate, and courage and hope shall eventually triumph over fear and despair. Since he is Superman, he is proven right.
To start with Code Geass, the supposedly Diabolical Mastermind wields a much friendlier power and has allies he can trust. And speaking of trust, he has become more stable and honest with himself, reinforcing his ties with the Black Knights. HE overall makes a lot more gains towards liberating Japan and suffers far less losses.
Neon Genesis Evangelion: Genocide sits comfortably in the middle of the scale. The story is dark but hopeful, and although bad things happen, there’s a light at the end of the tunnel.
Scar's Samsara has a very cynical main character as well as many dark scenes highlighting the crapsack nature of the setting, but the overall message is still very much on the idealistic side of the scale.
Oyabun tends to slide up and down the scale but keeps the point of middle on the cynical side. Considering it's a story about Naruto's descent/ascent (depending on the reader) into the Yakuza and criminal underworld with a mess of Gray and Gray Morality, it's to be expected. It becomes jarring to watch the optimistic Naruto slowly becoming a I Did What I Had to Do-type Anti-Hero / Villain Protagonist who is a little disillusioned with the world. He even considers making plans to kill Konohamaru, Sakura, Sasuke and Hinata when they find out he's still alive (he had to fake his death upon joining the Yakuza). He's like Pain minus the God complex.
Shinji and Warhammer 40k and Fairly English Story are both cynical, with heroes that do awful things and who have significant character flaws. However, both have a brighter aspect in that however monstrous the heroes may be, they are dedicated toward making the world a better place and have the strength and skill to do so. In Shinji and Warhammer 40k, this makes it slightly more idealistic than the original. Where Fairly English Story lands in relation to its parent source is...debatable.
Superwomen of Eva 2: Lone Heir of Krypton: The Evangelion setting is dark. So what happens when you throw elements of the Superman canon in the mix? A character was a Broken Bird and a Child Soldier and whose Abusive Parents had broken her and turned into a terrified, lonely, fragile, angry little child that drove people away to not be hurt again and thought she was worthless unless she was the best at everything gained super-powers, learnt to be a real heroine and better person and set to make her world a better place.
Thousand Shinji: It is hard telling what side of the scale this story falls into. On one hand, at the end of the history two billions of human beings have died and the survivors are ruled by dark gods that are preparing the human race for a war against a race of merciless murdering robots determined to kill everything. On other hand, it is a happier end than canon for both the main characters and humankind.
Ranma ˝ fanfics in particular are known for being more cynical than their source, often playing the more comedic elements straight.
Necaberints Phalanx is an interesting case. It's military sci-fi with a child soldier set in the Gears of Waruniverse and things keep getting worse. The main character has had a terrible life, like everybody else, and he's a going rather insane. It sounds like a complete wad of Dark Fic. It's actually rather cynical for a fic about a video game set in a post-apocalyptic hellhole where the good guys are Fascists. The themes of friendship, love, loyalty, camaraderie, and trust appear often and frequently, without the characters being True Companions, they would have all certainly died by now. It's a realistically idealistic work with cynicism jutting into it.
A good study on the differing ends of the scale occurs in Tiberium Wars. On the one hand, the story is cynical itself, with cruelty, necessary evils, senseless death, and disturbing brutality and violence. This is shown particularly well in a brutal moment where a Nod officer has to execute his own wounded because they'll slow his able-bodied troops down while retreating. On the other hand, the story also shows compassion, loyalty, and friendship are powerful forces that can let leaders command their men successfully and can let the dog soldiers on the ground survive the worst. The idealistic side is shown in a scene where Commander Karrde addressed a unit that had been mauled under his command, asking for volunteers for a dangerous mission. He expects them to refuse or deride him for getting so many of the troops killed, only to have the entire unit volunteer, believing that his command was the only thing that got them out of the battle alive.
Although never idealistic, With Strings Attached has the four gradually move from wide-eyed wonder and genuine heroic tendencies to exhausted cynicism by the end, to the point where they refuse to rescue Lyndess, who saved their lives in the First Movement. Slightly justified in that A) they didn't know if the curse on her had ended when the Dalns gods left, and it would have taken them weeks to get her home if it hadn't; and B) she was a skahs, and they were sick, sick, sick to death of skahs.
On the other hand, The Keys Stand Alone: The Soft World starts off with them being cynical and quickly sends them far down the scale, to the point where they decide that the so-called good Pyar gods and the White Tower are almost as evil as the Black Tower they're supposed to bring down. They aren't happy that they're being forced to support evil, but as John puts it, it would be a problem on Earth, but who cares what happens on C'hou?
Yet they firmly cling to their idealistic belief that violence is wrong and manage to stick to it.
Drunkard's Walk is generally idealistic. Most of the characters are shown to be (or become) decent people at heart, and it's very difficult to find character who is both truly selfish and not batshit insane.
The Emiya Clan is all over the place on this one, probably due to the different authors that make up the community and the many different stories and crossovers being written. Some stories, focusing on harem antics, family comedy, or the power of friendship are idealistic. Others, focusing on the more traditional Nasuverse angles, wars, and the criminal underworld, are extremely cynical.
Calvin and Hobbes: The Series starts out in the middle, just like the original strip. By Season 2, it's nudged a bit closer to cynicism than the original strip, what with all the snarkers and jerkasses, though most villains are harmless. Cerebus Syndrome nudges it a bit more, and Holographic Retro's death outright bumps it. It's still relatively idealistic, just less so.
Episodes like "Thunderstorm" and "Dark Laughter" definitely fit the cynical side more easily, however.
Game Theory (Fan Fic) plays itself pretty cynically, with being a deconstruction of the original Magical Girl Lyrical Nanoha though it also shows some of the idealism as well. Notably, while the conflict is essentially a case of Good Versus Good, Nanoha's idealism is actually portrayed as a flaw, as it leads to her siding with Precia, risking billions of lives for the sake of one person.
The thing is it works; the one person is brought back to life without any fatalities.
A in-universe debate is had between Danzo and Naruto in Naruto:Asunder before and after their fight. It should be noted that while Naruto is for idealism he sees the world in White and Gray Morality while Danzo is Black and White Morality.
Perfection is Overrated is somewhat on the idealistic side. It is emphasized that the world is often harsh and never can be perfect, but it's indicated that people can change for the better, and perhaps so can the world. In the end, The Obsidian Lord, the Usurper and the SUEs are defeated with the Himes managing to work together against the common threat, but the deaths of innocent people through the course of the conflict, as well as the lack of a Reset Button, results in there being more of a Bittersweet Ending than in canon.
Sonic X: Dark Chaos lies closer to the middle. Sonic and his friends are still heroes and hold their ideals, even if several of them are traumatized by the things they see. However, the rest of the setting is very, very, very, VERY cynical.
Necessary To Win is somewhat on the idealistic side Characters persist against considerable odds and while they may not always succeed, the fact that they are willing to try is considered admirable, and their efforts often bear fruit in and of themselves.
Oobserver of the Adventure Time universe has created three major stories centered around the Flinn pairing (Finn/Flame Princess), each of them lying on a different scale between the twosides.
The Citadel Of Truth firmly lies on the idealistic side as Finn and his crew goes on an adventure that remains as upbeat and positive as possible with Finn and Flame Princess hooking up early on with the majority of the plot dealing on the Ooocians dealing with the Big Bad Astrum. Most the villains also turns good via Finn's All-Loving Hero status, including the Astrum himself.
Yin-Yang: One to Ignite, One to Rekindle is in-between the two, as it deals with the angst of Finn and Flame Princess separating from each other, the former leaving because he believes that his actions could directly harm the two while at the same time, dealing with the issue of two featured Original Characters who also has the same problems as Finn and Flame Princess in addition to their relationship problems. Of course, through The Power of Friendship, they manage to make amends to their relationship and the fiction soon becomes more upbeat as the chapters passed.
Ember Alias however, is firmly on the cynical end of the scale, far darker than most Flinn fan fictions you will typically see (Second only to Purpose). Basically it deals with a lot more darker and cynical Finn, whom in his attempts to escape from his heartbreak from "The Red Throne", turns into a hero who prefers to help the needs of other people over his own doused heart and employs a disguise into a Fire Elemental in order to aid Flame Princess and Cinnamon Bun against the Olympians. However, this ultimate lie delivers heaps of negative consequences towards both Finn and everyone else, from suspicion that "Fenrir" murdered Finn, to potential wars and alienation from his former friends as a result of his altered identity.