Spirit of Winter's Chill by Jedi Sapphire (AO3). Rated PG, Gen, 8k. Summary: Sam and Dean are hunting Jack Frost. There's one important piece of information they don't have. No spoilers except to the premise of the show.
ao3.org/works/5342843
This is a fantastic winter holidays fic and case fic that involves a masterful treatment of the amnesia trope. This story totally lives up to its immediate hook. The best part is that the brothers' victory elicits you that melty (harhar) shmoop feel-good feeling you don't get in most straightforward case fics (but these are my favorite kinds of case fics).

This Still Remains by Jedi Sapphire . Rated PG-13, Gen, 5k. Summary: A young man wakes up in an abandoned house with a headache, no memories, and a tall companion who doesn't remember anything, either. Set any season
fanfiction.net/s/8840306
One of my all-time favorite tropes, amnesia. Fics that ask the question ‘how would you feel about and perceive those whom you love the most if you don't remember them? ' This fic is fantastic starting in media res with all these inexplicable brotherly fondnesses between Sam & Dean.

The Obeisance of Memory by rockpaperscissor. Rated PG-13, Gen, 139k. Summary: AU of season 4. COMPLETE. "Look, I've got no idea who your brother is, but uh, I think I might be him. Just, y'know, alive."
fanfiction.net/s/4822628
Canon divergences that still continue along the same general canon plot points and timeline aren't super my thing, but I ripped through this story to see what would happen. Fantastic premise. This fic is also in my alternate seasons 4 & 5 reclist

Blue Skies From Rain series by lovesrain44. Rated R, Sam/Dean, 177k. Summary: The morning after Sam rescues Dean from the djinn, Sam and Dean go back to the warehouse to take care of the bodies of both the victims and of the djinn. But instead of what should be a simple clean-up job, Sam and Dean are sucked into a nightmare world brought about by the djinn's last dying act of revenge. (Takes place directly after What Is and What Should Never Be.) What do you do when you wake up in a mental institution and you think your brother is dead?
ao3.org/series/11774
This fic you could just feel the mental institution 's dismal atmosphere seeping into you, always cold and clammy, traumatizing ‘consequences ' for ‘misbehavior ', cafeteria slop, a dreary sterile building, and a terrified amnesiac!Sam who 's kind of mentally regressed & helpless & doesn 't recognize Dean 😭. I 'm pretty sure I 've read this fic twice. There 's just so much of a "we found love in a hopeless place" feel to it, and that 's one of my favorite themes.

Courting Death by theproblematique. Rated R, Dean/Sam, 50k. Summary: Sam Winchester lived the first six months of his life in a happy family; the next twelve years as John Winchester 's only son, and the last decade as an orphan. He 's supposed to die at twenty-two trying to save the woman he loves from a fire, because he doesn 't have a brother to pull him back. But the night Sam meets his Reaper he discovers that Death is overly fond of pop-culture references, too beautiful to be real, and reluctant to kill him.
ao3.org/works/875482
This fic is one of my top favorite spn fics . I love this alternate universe where Dean 's this wise-cracking reaper that reluctantly develops a fondness for a piteous Sam that turns out to be significant beyond expectations in the best way possible for a love story narrative. Amnesia fic!

Where Do We Begin (The Rubble or Our Sins?) by dimeliora. NC-17, Sam/Dean, 40k. Summary: AU post season one. He wakes in a hospital, missing a limb and all of his memories. They tell him he is Dean Hunt. That his sister died in the accident that claimed his leg. From there he rebuilds with the help of his quirky lesbian neighbors and a homeless drifter named Sam.
ao3.org/works/1025195
Amnesia curtain fic yaaaaas! I love this pushy idea of the unique ensemble of real-feeling characters that surround Sam & Dean as they settle into the curtain fic they 're in. It 's just precious, y 'all.

What Remains by merrin. Rated NC-17, Sam/Dean, 39k. Summary: In Jefferson, Texas a man ends a generations-old curse and saves all the town's children, but completely loses his memory in the process. When it's discovered that he's a wanted criminal, the town comes together to conceal him out of gratitude for what he's done for them, giving him an apartment, a job and a whole new life. It takes seven months for Sam to find Dean, and when he finally does, he has to adapt to being around a man who has no idea that he used to be Sam's brother.
ao3.org/works/130952
It 's been awhile since I 've read this one but I remember some very tasty angst!

I See the Moon by kaylennz. PG-13, Dean/Sam, 88k words. Summary: Sam had known how Dean felt about him when he'd left for Stanford. His own feelings weren't so clear. He'd needed time away from it all, hunting, his father, and especially Dean. It took him five years and a degree he hadn't planned on to realize there was only one person he wanted to share his life with. He'd never considered the possibility that Dean would move on without him...or that something could happen that would erase him from his brother's life completely.
ao3.org/works/799092
Daddy!Dean and broken-hearted!Sam looking for his big brother, and of course happy endings. This fic had a lot of wonderful moments. Also in my daddies reclist .

Dragon Spell by virtualpersonal and brimstonegold (LJ). Rated NC-17, Sam/Dean, 112k. Summary: Crossover with Anne McCaffrey 's Dragonriders of Pern. Snooping around in his father's storage locker, Sam touches something he shouldn't and gets sucked into a world where dragonriders must protect their world from a continuous threat of threadfall. Dean follows and finds Sam has lost his memories. Until they get out of this mess, they have to ‘make like the natives. '
virtualpersonal.livejournal.com/206751.html
This story was my gateway fic to dragon AUs and it's been ah👏ma👏zing👏 reading and exploring this one and all the others! While it 's a crossover with Anne McCaffrey 's Pern universe, I had no idea and rolled with it anyway, so you definitely don 't need to have read the McCaffrey 's series to understand this story (but it 's a great in that it gives you the gist of what other Pern x SPN fics incorporate in their crossovers as well). Love the amnesia trope deftly used here to kinda excuse/explain how the wincest unfolds, haha

Deja Vu by Zara_Zee . Rated NC-17, Jensen/Jared, 47k words. Summary: Dean Winchester has a pretty sweet life. He works in construction; he married his long-time girlfriend, Carmen, straight out of high school; and he 's almost paid off a basic apartment in the Middle District. He may never have left his home district, let alone his home planet, but he 's happy… more-or-less.So why does he keep dreaming about the red wastelands of Mars? Why does he know more about the Martian Resistance than he has any right to? And who do the long, long legs and decidedly male butt that have him waking up achingly hard every morning belong to? Maybe Dean just needs a holiday? He couldn 't afford a real one, of course, but maybe he could go to Déjà Vu and get the memories of a holiday implanted; get Mars out of his system.Of course, that 's when the trouble really starts.
ao3.org/works/4452290
This was so great. Yay suspicious forced amnesia! So easy to read (meaning great world-building while moving the plot along) and the anticipation for Jensen to meet Jared was brilliance. Discovering why Jensen was brainwashed was so compelling and exciting too! This fic is featured in my SPN... IN SPACE! reclist and my movie fusions reclist as well bc it's based off Total Recall (1990)

The Last Light I See by pennydrdful. Rated R, Jared/Jensen, 26k words. Summary: When Jensen wakes up in the hospital, he wakes up confused and alone. There 's no family or friends worrying over his bedside, no cards or flowers. The doctor quietly informs him of three things: his name, that he was beaten and mugged, and that he 's tested positive for Super. On the long road of recovery from a brutal attack, Jensen slowly starts to piece together what kind of man he was, the kind he wants to be, and why the tall, ridiculously gorgeous gardener seems to hate his guts.
ao3.org/works/5007877
The summary alone is so eye-catching, right? Amnesiac super with an angry gardener?! What?! Well newsflash: it 's 100% worth finding out.