Sinestro finally gets Oa destroyed, but he loses his own life in the process. Kyle, John, Kilowog, Soranik, Salaak, Arisia, Ch'p, Katma, Tomar Re, and Sodam become the new Guardians of the earth battery, which only survived because Hal merged with the light.
Barry Allen returns after surviving the Crisis on Infinite Earths. Realizing that Central City has long moved on after he disappeared and that Earth is safer than ever, he moves to the future with Iris [so that his climax is CoIE but he still gets his happy "silver age" ending]. The Rogues retire and Wally remains the guardian of the city.
Ryan and Ray find a way to cure Jean from her Jimbaran relapses. Ray decided to retire as the Atom to focus on his marriage.
Justice League International
Booster Gold makes the ultimate sacrifice, which only a resurrected Ted will ever acknowledge. Ted becomes the new "Maxwell" of the last JLI [it's a switcheroo deal topped with a "Greatest story never told" situation], which also has Fire as its field leader. Ice retires to have a family with Guy... What none of them ever find out is that Maxwell's actual brain remains in his old cyborg body; he retired long ago and has lived with L-Ron and Wanda managing a Manga Khan space resort ever since.
Wonder Woman saves USA from the wrath of the Gods, her body becomes a statue at Washington and Zeus gives her soul, along with Steve's a place in Mount Olympus [CoIE + Greek tragedy].
The Joker and a small gang of old time criminals push Damian betray his father and Terry. Damian sacrifices taking the Joker with him. Eventually, Bruce dies by Selina's side surrounded by Terry, Barbara, Dick and Tim [It's a legacy thing, he made a difference]. He's buried by them, along with the remaining leaguers and the Batman Inc. Corps.
The Elongated Man
Ralph and Sue keep solving DC mysteries forever [Quantum Leap, anyone?]. Billy Warner becomes the best detective of his generation, the Detective Chimp invites him to join the Croatoan Society.
The Martian Manhunter
The Martian Manhunter retires to live with a single mother and her daughter [is, he embraces humanity]. They die at the same time from natural causes.
Dinah and Ollie remarry, only to get divorce the next year after that. They remain a couple. They have a daughter; she becames a registered Republican and wants nothing to do with superheroes.
It took a thousand reincarnations, but Hawkman and Hawkgirl finally complete their lives without early tragedies.
Zee finally starts a drama-free relationship with a normal guy and retires [she got over her daddy issues]. She becomes a hot soccer mom. Her kid is teased because there are a lot of "glamour" pics of her mom all over the Internet.
Not an important character, but Starman sacrificed himself to save Earth from his own race [Ziggy style], which were actually mutants created by the Spiders from Vega.
After Aquaman achieves great peace between Atlantis and the rest of the World, and a lot of prosperity emanates from his county, he dies in a fight against One's son, who was then killed by Garth, who was, at the time, considered a traitor to the kingdom. This way, Garth gets this way his redemption, as well as the forgiveness of Meera and Atlantis. He is finally allowed to reunite with his Atlantean wife: Arthur's daughter.[something Arthurian without making Mera a **** or dragging swords and lakes into it].
Black Lightning reveals his identity and becames Mayor of Metropolis [he finally made the difference. Would President be too much?]. The Suicide Slum becomes the Suicide District, the cultural center of the city (real state agents keep trying to push for "Simon Heights", but nothing). He puts on his wig for one more fight along the League after that.
Java takes one of Simon's plan to the extreme, and kills Sapphire; Simon kills Java trying to save her. Although old habits die hard, Simon rejects his own selfishness for her and his grandson; Metamorpho accepts himself in order to provide a role model for his son, he gets Simon's frequent cooperation as a grandfather.
Justice League Unlimited
The Justice League is carried on by Terry.
Mr. Mxyzptlk puts Superman him through some ultimate test of morals and courage. He passes and the imp alters reality so that his enemies fade away. However, many years later, Luthor returns and things too far in order to destroy him (probably something involving the Anti-Monitor technology from Crisis on Infinite Earths). He is a shell of a man, merged with Brainiac, Amazon and Metallo technologies, and he makes Superman chose between sacrifice or the destruction of all reality. Superman chooses the former and dies. Right then, after realizing that he has lost his humanity and has almost destroyed everything he ever cared about in the process of eliminating him, Luthor commits suicide. It turns out this was Mxyzptlk's real test. He pops up again to restore everything, only this time he leaves Clark without his powers, thus lifting the overwhelming responsibility from his shoulders, so that he finally has no other choice than to spend the rest of his days living a normal life with Lois and their half Kryptonian son. Karen retires to lead her own life with her family. Kara married Jimmy and along with Krypto, she proudly carries Superman's legacy.
The Kents retire to live in the old Smallville farm. Every day Clark looks more like Jonathan.