I've got something for #2:
So an Archer and a Hunter Walk Into a Bar (http://www.fanfiction.net/s/8338092/1/So-an-Archer-and-a-Hunter-Walk-Into-a-Bar)

#4 Crossovers! I could read these again and again! =D
Dark Angel/Supernatural:
i) The Wellspring (http://www.fanfiction.net/s/5021619/1/The-Wellspring)
ii) The Time Alec Got Hustled By An Ordinary Old Guy (http://www.fanfiction.net/s/5157127/1/The-Time-Alec-Got-Hustled-By-An-Ordinary-Old-Guy)
iii) Flawless (http://www.fanfiction.net/s/4946249/1/Flawless)
iv) Manmade Monsters (http://www.fanfiction.net/s/3113897/1/Manmade-Monsters)

X-Men/Supernatural:
i) Wolverines, Wendigos and Winchesters (http://www.fanfiction.net/s/5155714/1/Wolverines-Wendigos-and-Winchesters)

His Dark Materials/Supernatural:
i) Atoms of me and you (http://www.fanfiction.net/s/9046855/1/Atoms-of-me-and-you)
ii) Daemon'Verse (http://www.fanfiction.net/s/5790663/1/Daemon-Verse)
iii) The Rare One (http://www.fanfiction.net/s/8487433/1/The-Rare-One)
iv) He Stands Alone (http://www.fanfiction.net/s/9011584/1/He-Stands-Alone)

Firefly/Supernatural:
i) Ending of an Era (http://www.fanfiction.net/s/5670246/1/Ending-of-an-Era)

Star Wars/Supernatural:
i) From Perdition (http://www.fanfiction.net/s/5929445/1/From-Perdition)

Star trek/Supernatural:
i) The Tamir Incident (http://www.fanfiction.net/s/7579603/1/The-Tamir-Incident)

Criminal Minds/Supernatural:
i) Sour Cherry Pie Life (http://www.fanfiction.net/s/7050961/1/Sour-Cherry-Pie-Life)
ii) All the King’s Horses (http://www.fanfiction.net/s/5785894/1/All-the-King-s-Horses) and it's unfinished sequel
iii) As You Are Now, So Once Was I (http://www.fanfiction.net/s/5797980/1/As-You-Are-Now-So-Once-Was-I)

Enjoy!~

awesome thank you ive read some of these be fore but i lost the like to some of them thanks heaps

No problem! There was another fanfic crossover that I was looking for and it's a Lie to Me*/Supernatural crossover, and I managed to find it. It is quite interesting :D

The Truth Lies Beneath (http://archiveofourown.org/works/439132/chapters/748399)

nice thank you

There is a story that's based on the fairy tale of Hansel and Gretel, it's J2 though and not really a crossover. And it was in the world before Jeremy Renner ever got to be Hansel ;-) It's good, though, so maybe you'd like that anyway?

Man in a Candy Store (http://morrezela.livejournal.com/14666.html)

Also, there are several timestamps for that.

awesome tank you

# 4

Learning How to Fly - Supernatural/Stargate Atlantis
http://faithburke.livejournal.com/11708.html (http://faithburke.livejournal.com/11708.html)

Off on a Tangent: An 'It's all in the Details' Side Story - Supernatural/Stargate SG1. One shot, crackish. Gabriel and Castiel meet Jack O'Neill.
http://www.fanfiction.net/s/8849255/1/Off-on-a-Tangent-An-It-s-all-in-the-Details-Side-Story (http://www.fanfiction.net/s/8849255/1/Off-on-a-Tangent-An-It-s-all-in-the-Details-Side-Story)

When Worlds Collide Supernatural/NCIS. WIP.
http://www.fanfiction.net/s/9018850/1/When-Worlds-Collide (http://www.fanfiction.net/s/9018850/1/When-Worlds-Collide)

There was also Those Campell Boys (Supernatural/Criminal Minds WIP) but it disappeared from FanFiction.Net.

awesome thanks

#4

I´m So Far From My Home by Supervillegirl
www.fanfiction.net/s/6118962
SN/DA

Dean and Alec Save the Day by deanaholic
www.fanfiction.net/s/2691653/1
SN/DA

sweet thanks

Ok, a lot of these are Dean/someone; also I second the DA/SPN, post a:

Captain Picks the Ship (Science Officer Shuts His Cakehole) (http://archiveofourown.org/works/619540) by clex_monkie89
- Star Trek, gen
- Dean stumbles ass-backwards into everything in his life, and it's usually Sam's fault.

We've Already Lost Indiana (http://archiveofourown.org/works/138007) by newredshoes
- West Wing, gen
- How Toby Ziegler ruined Dean Winchester's life, and Sam failed to inspire a keystone policy of Josiah Bartlet's re-election platform.

Of A Sort (http://ignipes.livejournal.com/255958.html) by ignipes
- Harry Potter
- It was the longest Sorting in recent Hogwarts history.

The Wellspring (http://scourgeofeurope.livejournal.com/38445.html) by scourgeofeurope
- Dark Angel
- Sam and Dean find a tiny smartass in a barn. What are they to do?
* at bottom is a link to a similar verse

Like a Bad Joke (http://archiveofourown.org/works/92883) by tuesday
     - with True Blood
     - An angel, a demon, and a vampire walked into a bar.

Old Country (http://archiveofourown.org/works/164479) by Astolat
   - with Harry Potter
   - Sam and Dean go to Hogwarts (Sam/Dean)

Not With a Bang, But a Whimper (http://members.cox.net/devilc/SPN-SCCNotWithBang.html) and the sequel Not With a Whimper, But a Bang (http://members.cox.net/devilc/SPN-SCCNotWithWhimper.html) by DevilChild
    - with Terminator: The Sarah Connor Chronicles
    - Derrick meets Dean...again. (Derrick/Dean)

The Time Has Come to be Gone (http://jujuberry136.livejournal.com/46866.html) and the sequel When You Are Done (http://jujuberry136.livejournal.com/64647.html) by Jujuberry136
      - with Criminal Minds
      - One of the FBI’s most wanted is unexpectedly apprehended.
 
How Ianto Jones Quits His Job and Decides to Take Over the World (Without the Help of a Kangroo Arm) (http://sparky77.livejournal.com/631491.html) by sparky77
     - with Leverage and Torchwood
     - They become friends and hang out and stuff. (Dean/Jones/Hardison)

Dearly Divided (http://archiveofourown.org/works/31497) by JayneLeitch
   -  with Dexter
   - "What's a nice girl like you doing in a rat trap like this?"/"Hunting monsters." (Dean/Debra)

Black-Throated Wind (http://archiveofourown.org/works/123537) by topaz
    - with Angel
    - He lunges for the journal like he knows what he's going to find, and when he looks up, Dean's rolling to his feet. (Dean/Lindsey)

post b:

Stir of Echoes (http://archiveofourown.org/works/64251) by frenticfloetry
   - with Grey's Anatomy
   - Between the black of firsts and white of lasts are countless shades of gray, some too subtle to matter in the moment. (Dean/Izzie)

Good Deeds (http://nixa-jane.livejournal.com/83357.html#cutid1) by nixa jane and the sequels Rewards (http://fcolfanfic.livejournal.com/1375.html) and Familiar Intimacy (http://fcolfanfic.livejournal.com/1745.html) by ForCryinOutLoud
  - with SGA
  - "Oh god," Rodney said, eyes flickering towards the road and back. "You're not some escaped mental patient, are you?" (Dean/Rodney)

Coeur d'coeurs (http://lyra-wing.livejournal.com/179115.html) by lyra_wing
  - with Pushing Daisies
  - Dean and Sam open a pie shop.

Ride the Lightning (http://ratherastory.livejournal.com/169234.html) by ratherastory
   - with Stonehedge Apocalypse
   - Three years after her father consented to be Castiel’s vessel for the second time, Claire goes to find her Uncle Jacob.

All In the Game, Yo (http://sonofabiscuit77.livejournal.com/23985.html) by sonofabiscuit77
   - with The Wire
   - Dad was shot and killed by a police officer when Sam was five. (Sam/Dean)

SG-5 (http://deancastiel.livejournal.com/1140166.html#cutid1) by ravensilverwing
  - with Stargate
  - He’s tempted to check his contract, but despite the fact it contains many and varied crazy things, he’s pretty sure accepting a tax accountant stalker is not one of them.

The Awesomes (http://blue-fjords.livejournal.com/87073.html) by blue_fjords
   - with The Incredibles
   - Twenty years after going into hiding, the former Mr. Awesome and Righteous Man are attempting to raise their family in peace and quiet.



Also screencaps of SPN/Jurassic Park crossover (http://evewillow.tumblr.com/post/48613691634/team-free-will-jurassic-park-au)

awesome thank you

#4

I have a crossover tag, if you fancy a browse, i have rather a lot ......

http://previous.delicious.com/chellexxx1/SPN+xover

hope you find something you like

xxx