brightly_lit has a bunch of good preseries gen fics. Here are two of my favourite:

Stuck (http://archiveofourown.org/works/680803)by brightly_lit
- Things go from bad to worse in a small Wyoming town until teenaged Sam and Dean are stranded in the middle of nowhere in a blizzard, where there's nothing to do but talk about all the things they've never been able to before--things that may be better left unsaid. At least maybe now Dean can try to fix whatever's going so wrong inside Sam that's made him silent and cold all these months, that's made him willing to let Dean have what's left of their food. Too bad Dean's never been good at fixing anything.

Alien (http://archiveofourown.org/works/731404)by brightly_lit
- This is the story of when Sam went to Stanford and figured out, with a lot of difficulty, loneliness, and false starts, how to make his way in the normal world without the family that had defined his whole life for 18 years. (Mainly gen with some het)


The Crow on the Cradle (http://kroki-refur.livejournal.com/72426.html) by Kroki Refur
- On October 2, 2005, Sam Winchester walked out of the apartment he shared with his girlfriend Jess in the middle of the night, and didn't come back. Sam/Jess

In the Backseat (http://www.fanfiction.net/s/2850937/1/In-The-Backseat) by fieldofyellowdandelions
- What if Max hadn’t committed suicide? What would have happened to him then? AU to Nightmare. Max's pov.

Privilege of Choice (https://www.fanfiction.net/s/6382203/1/Privilege-of-Choice) by Mousme
- When a hunt goes wrong, John is forced to make a decision no parent should ever have to face. Pre-series, teen!chesters. (Warning: this has spoilers for Season 2, specifically what John told Dean to do in 2.01. Don't read if you haven't watched that yet)

Indirect Proof (https://www.fanfiction.net/s/3938325/1/) by starliteyes
- Dean's not just any brother. (Set pre-series but has spoilers for the last episode of Season 2)

Contact (https://www.fanfiction.net/s/3183800/1/Contact) by Deanish
- A 'what might have been.' What if the demon had stayed in hibernation for just a little longer? Sam/Jess


Not sure if you mind self-recs or not but I've written a pre-series Sam-centric genfic.
A Normal Life (http://rirren.livejournal.com/3863.html)
- Sam is doing his best to make a life for himself in Stanford, but almost two decades of the Winchester lifestyle have taken their toll. Once he's away from hunting and those constant, life-threatening situations that kept everything under the rug, his long-dormant PTSD flares up.


Edited 2014-02-25 08:51 pm (UTC)

Shut the Gates at Sunset (http://soncnica.livejournal.com/4472.html) by soncnica.

Summary: Shut the gates at sunset, after that you can't get out. A case finds Sam.

It's Season 1-ish and quite brilliant.

I will never stop reccing In Reverse by sodakey I think it's just too good of a story to pass up. https://www.fanfiction.net/s/2787883/1/In-Reverse (https://www.fanfiction.net/s/2787883/1/In-Reverse)
summary:After Faith, a job has the boys looking for missing hikers in Wyoming. While Sam worries it’s connected to what happened to Dean ten years ago, Dean wonders if Sam would be better off back in the world of normal.

I'm not quite sure the timeline in this one but it has Bobby and I don't think there's Castiel in it.
In Darkness Let Me Dwell by Muffy Morrigan https://www.fanfiction.net/s/4367070/1/In-Darkness-Let-Me-Dwell (https://www.fanfiction.net/s/4367070/1/In-Darkness-Let-Me-Dwell)
summary: Bobby calls Sam and Dean for help hunting a demon that demands human life. When Dean becomes a victim, Sam struggles to save his injured brother before Dean is lost forever. Hurt!Dean. Angsty protective Sam. Not death fic NOW COMPLETE

This has graphic torture, and child molestation so please read at your own risk.
Last Child by JackFan2 https://www.fanfiction.net/s/6241402/1/Last-Child (https://www.fanfiction.net/s/6241402/1/Last-Child)
summary: When Sam becomes ill, Dean's so-called routine questioning leaves him the unwitting target of the very thing they were investigating. Suddenly, it's a race against time and Sam scrambles to save Dean from something neither of them expected. Hurt!Dean

Less Traveled By by Mirrordancehttps://www.fanfiction.net/s/6428368/1/Less-Traveled-By (https://www.fanfiction.net/s/6428368/1/Less-Traveled-By)
summary: High school is hard enough without an absentee father, restless spirits, haunted cars, a missing classmate and a sexual predator on the loose. Then again, the Winchesters never did anything the easy way. Dean is 17 and Sam is 13.

This verse is pretty good too. Strangers and Angels by reading https://www.fanfiction.net/s/2748108/1/Strangers-and-Angels (https://www.fanfiction.net/s/2748108/1/Strangers-and-Angels)
summary: Worn out, the boys stop at a remote motel to get shelter from a storm.

Mistakes Were Made by film princess https://www.fanfiction.net/s/5045693/1/Mistakes-Were-Made (https://www.fanfiction.net/s/5045693/1/Mistakes-Were-Made)
summary: Sam and Dean stumble across a delusional Victorian spirit who desperately wants her two boys back. As far as she's concerned, the Winchester boys would make acceptable substitutes. Teen!chester story. Sam is 13 and Dean is 17.

No Traveler Returns by JennK528https://www.fanfiction.net/s/2818114/1/No-Traveler-Returns (https://www.fanfiction.net/s/2818114/1/No-Traveler-Returns)
summary: The boys hunt a ghost in Charleston. And Dean's in trouble....

I wasn't sure if I hit the word count limit or not. I think I still have some more recs somewhere.

Pied Piper by JennK528 https://www.fanfiction.net/s/3165636/1/Pied-Piper (https://www.fanfiction.net/s/3165636/1/Pied-Piper)
summary: Someone is collecting unusual children. Children rather like Sam. Unfortunately, Dean and Sam discover why.

Not sure the timeline on this one but it's a case story. This was put as horror/drama. Red by BigPink https://www.fanfiction.net/s/3169840/1/Red (https://www.fanfiction.net/s/3169840/1/Red)
summary: Something evil is killing treeplanters in the forests of the Pacific Northwest, possibly the same predator that Dean narrowly escaped years before. How Grimm will things get before the brothers figure it out? COMPLETE

Oh and here's a funny story I saved. Special by Lady Ophelia https://www.fanfiction.net/s/2826655/1/Special (https://www.fanfiction.net/s/2826655/1/Special)
summary: At a parentteacher conference, a principal expresses some concerns to John Winchester. His sons are special... very, very special.

The Wake Up Call by November'sGuesthttps://www.fanfiction.net/s/2943438/1/The-Wake-Up-Call (https://www.fanfiction.net/s/2943438/1/The-Wake-Up-Call)
summary:How will the Winchesters pick up the pieces of their lives following the events in Devil's Trap? While in a coma, Dean reaches out to Sam the only way he knows how and John sees that the cost of his revenge may not be worth it.

I'd also like to rec this author. https://www.fanfiction.net/u/3064788/Sharlot (https://www.fanfiction.net/u/3064788/Sharlot)

Yeah I think that's all I've got for now. Enjoy. :D

for incomplete look here
http://spnstoryfinders.livejournal.com/5897628.html

check with billy, she has incompletework2's fics (including jared and chris stories). you can see the lists here: http://billysgirl5.livejournal.com/359412.html