Gunnerkrigg Court, so far at least. There's lots of grim details in the background, particularly the details of Annie's Parental Abandonment, and her extensive prior experience with the Psychopomps, as well as poor Robot's misfortunes. The main characters remain well-balanced and optimistic in spite of these, and there's nothing to suggest that this is naivete on their part.
In The Order of the Stick, the Order visits an Oracle who tells everyone on the team the answer to one of their questions. The Reveal heavily implies the imminent death of one member, the ultimate demise of a second, the corruption of a third, and the fall of a prominent good nation because a fourth phrased his question poorly — even after the Oracle heavily hinted this last one. While a fifth's foretelling is positive, only the ending to Elan's story is guaranteed to be happy, and Roy advises that it will be something he has to work for rather than just wait around for.
Ally from Fans! Dear sweet fancy Moses, Ally! During the first five books of the series, she overcame a terminal illness and her own nihilistic dark side, frequently attempting to push her husband Rikk away from her and toward Rumy for his own good. Not helping the fact that Rumy herself is the poster-child for I Want My Beloved to Be Happy, and has invested much of her self into helping Rikk and Ally to be happy, while Rikk cares too much for both of them to simply cast either one aside(and himself suffers from Chronic Hero Syndrome). By the end of book five, Ally invokes the Third Option, that she, Rikk and Rumy form a triad marriage. She lampshades this a little in a later chapter that dwells on their first months as a triad, when she informs Rikk, "Happy endings ain't for wimps."
In the Polandball comic "The Autonomous Region Of Åland - "A Romantic Tragedy"", Sweden loses his love for Åland and they eventually drift apart due to being separated by both the Russian Empire and Finland for so many years(and getting mocked by Denmark and Norway for being a "crybaby"), but Åland just ended up being an annoyance to Finland and Sweden is implied to have found love again with Thailand.
Though our beloved characters in Homestuck may have died a lot and lost various family members and friends along the way, it's certainly shaping up to be this. And hey, it did. It took years, endless terrible timelines, multiple universes, and a ton of death and tragedy on the way, but they won the game at last, and their prize is a wonderful new world they can finally call home.
Two Sides Sebastian is a Pretty Boy that's a Clueless Chick Magnet that Even the Guys Want Him yet can't focus on that due to his home life consisting of a Missing Mom and deadbeat alcoholic father that he has to focus on how to pay the bills even in school. He reluctantly helps his loser friend who bragged about having a girlfriend by having to dress as a girl to play his girlfriend down to kissing him then due to riding the subway home, gets felt up and agrees to have sex with the stranger for money, which leads a lucrative career in prostitution that he finds himself enjoying. However, the school principal finds out and blackmails Sebastian to coerce him into sex, where Sebastian is also abused enough to leave a mark. Fortunately, Sebastian's boyfriend, Damian finds out and is pissed and blackmails the principal back by filming him about to rape Sebastian, (in drag this time) to leave them alone. Damian declares he'll always protect him because he loves him and it ends with The Big Damn Kiss.