'Cause, okay, I love shippy stuff, and I like clever plots, but it's all in the DETAILS, man! Like, weird classes you're required to take at Starfleet Academy, a Buffyverse species of demon that can only be killed by a certain frequency of sound, babyproofing a Potterverse house when the baby can do magic, etc. Explore the quirks of your canon universe! So, have some awesome worldbuilding fics:
The Recreation of the Warrior - Gene Roddenberry's Andromeda, Harper/Tyr, Tyr/others, Dylan/Beka, Dylan/others, Beka/others. Amazing exploration of Nietzschian culture and philosophy. "My people learn as small children that religion is the opiate of the masses. In practice, however, we spend far more time acknowledging our debt to our ancestors than might be expected of any Confucian monk. Since no actual deities are involved, this does not count as 'religious observance,' but merely as practical genetics." Gah, just. Tyr's voice is so strong and so consistent that it totally negates my antipathy toward first person POV in fic.
Cradle Elbows Wide - Firefly, gen. This is Sergeant Mal, guys, and it's so well-written that it's totally canon to me. All the different cultures that sent soldiers for this one cause, and we know the whole time that the cause is totally doomed; it kills me, but in the best of ways.
Reconstruction and the companion piece,
Restoration - Buffy the Vampire Slayer, Xander/Spike, Willow/Tara. A post-Gift AU that does a fantastic job showing the struggle to guard the Hellmouth without your heavy-hitter. The CotH is the BEST, god; it makes so much sense and it's so very, very awesome. But there's also the protective stalking of Dawn, the Omega Plan (GENIUS), just a million little touches that bring the 'verse to life.
Father Goose Tales - Buffy the Vampire Slayer/Law and Order: SVU/Alias/Las Vegas/Gilmore Girls/Stargate SG-1, Xander/Faith, canon pairings. Guys, there's infrastructure and standard operating procedures! There's a supernatural troubles hotline! It's very much a world where the Council has a presence, complete with unintended consequences, and where the Council is an organization of professionals who have been there and done that. "Hello, you’ve reached the North American Headquarters of the Watcher’s Council, if this is an emergency please scream or press one ….. if this is not an emergency, please leave a message and a method of contact and we will get back to you. If you would like to be contacted by one of the regional offices, be sure to make that request and include your location in the message. Thank you and be safe. ….. beeep."
The Sacrifices Arc - Harry Potter, Harry/Draco, Snape/Regulus, Hermione/Zacharias, Connor/Parvati, a bunch of OC relationships that are amazing and run through het, slash, and femslash. Oh, y'all knew I was going to throw this one in there. So! This 'verse explains why there were no international efforts to stop Voldemort, gives us interesting and well-drawn systems of magic that include the awesomeness of something called "puellaris witches" - women who, through circumscribing their behavior in public and submitting to their husbands, gain the ability to turn into fucking lionesses when their children are threatened, aaaand shows us once again that humans rule the world because they are assholes. Um. I also don't feel comfortable sending people off to read this without mentioning that this shit is HARDCORE. Like, I read something that had a bunch of dire warnings for what ending up being an apocalypse, some violence, and some implied sex slavery (all of which got reversed and wiped from the characters' memories, so, weeeeeak). This is not like that. There is torture of main characters, including loss of limb. There is death, lots of it, major and minor characters, including a baby (in a fairly horrific way). There is rape, not of major characters, but there's an unrepentant (female) rapist who's one of the "good guys" and somebody gets raped to death, so. There is child abuse, physical, emotional and magical. I'm forgetting some stuff. Okay, cannibalism! There is cannibalism, by bad guys and also by a good guy under mindcontrol. ...Read it anyway! It is totally my favoritest story in all the worlds.