Main SPN Universe:

Second Chances
SPN 5x04 "The End" Coda - Future Cas gets one last wish. Dean/future!Cas (sorta)

And the Stars Softly Fell
SPN 5x04 "The End" Coda (future!verse) - Lucifer!Sam says goodbye to a dying future!Cas. Slight Dean/Cas

Mistake
SPN 5x08 "Changing Channels" Missing Scene - Where Gabriel sent Cas that got him all bloody

Whispers
SPN 5x19 "Hammer of the Gods" Coda - Gabriel


Slight-to-Major AUs - Gabriel and Castiel as brothers:

Grace Trilogy
Goes AU after 5x08 - Gabriel and Cas bond, then Dean and Sam get added in. Three fics, now complete:
Grace
Storm
Bond (cutscene: Healing)

Brothers
Goes mildly AU post-5x16. Includes pissed off Raphael, who appears to be the main villain in all my Gabe/Cas fics

Dulce
Sort of Coda to 5x18, but includes Gabriel (obviously). Gabriel finds his little brother after the battle and banishment

Center
Set in some distant, future Heaven. A conversation between Gabriel and Castiel

Dreams
Tiny Gabe/Cas double drabble, random timesetting

Glass Houses
Small conversation ficlet, random AU where Gabe joined Team Free Will

Valley of the Shadow
Post/During 5x22, poss AU after. Castiel rescues Gabriel from one of the darker Judaic afterlives. Parts I, II and III

A Brother's Hand
Coda to 5x16, Cas/Gabe. He stands empty, and his brother comes.

Uriel Ficlets
Putting them here because they don't make sense elsewhere. Not Cas & Gabe, but 2 ficlets featuring Uriel's reconcilliation with both of them. Vaguely post 5x22

Healer's Fury
Same story as above, only Gabe and Raphael, this time. Set mid-S5, ish?


Fics Crossing with Norse and Other mythologies:

First and Last, and First Again
SPN 5x19 "Hammer of the Gods" Coda - Gabriel, Kali, Loki, crossover with various myths
And sequel Once, And Then
AU version of 5x22. The gods, plus angels and Winchesters, go kick Lucy's ass

Mythology Meme
Not a fic, as such, but amusing nonetheless. Various myth-crossover scenarios involving Gabe and Cas

Weregild Verse
Series of stories operating on the idea that Gabe possessed Loki as a Vessel way back when, and subsequently fell in love with him. Main parts are set Post 5x22 (post canon), ficlet series is pre- and during canon.
Ongoing.

Monsters
Random ficlet. Not Gabriel this time, but SAM. Sam and Fenrir on the nature of monsters.

First Kill
Random Gabriel/Kali ficlet for a prompt

Fly in Amber
Castiel fic, coda to 5x18, crossing with Voodoo myth

Elysian Fields
The run-up to 5x19 from the gods' POV

Chances
Prompt ficlet. Sam and Dean meet two of Loki's kids.

Taunting the Tiger
Prompt ficlet. Gabriel, Kali, croquet, and Lewis Carroll.

Game Night
Prompt ficlet. Gabriel, Loki and family (plus the Good Omens boys) play monopoly


Pairing Fics, Random Timesettings:

Cream
Dean/Cas ficlet set vaguely in early S5

Rhythm
Dean/Cas ficlet set somewhere mid-S5. Wing grooming!

Doorways
Sam/Gabriel ficlet set somewhere post 5x08, possibly AU

The Deal
Gabriel/Crowley fic set post 5x22. Not exactly AU, but does a slight end-run around canon ...

Some Fundamental Thing
Castiel/Gabriel ficlet, indeterminate timeframe. Light R.


Highlander Crossovers:

Prometheus Unbound
Methos, SPN Death. Basic idea that Death is Methos' father.
Set in roughly the same universe as this ficlet

This ficlet, however, has the same idea, but Methos doesn't know


Good Omens Crossovers:

Arrangements-verse
Crossover between Good Omens and Supernatural, set roughly twenty years post-book for GO, and somewhere after 5x16 (going AU from that point) for SPN. Spoilers up to those points.
Ongoing.

Celestial Red Cross and sequel Exercises in Patience
Crowley and Aziraphale are drafted to look after battered angels. Including Castiel and Gabriel. Hilarity ensues.
Complete (for now)

Remnants verse
A much darker verse, where after the GO Apocalypse, Aziraphale was captured by Zachariah and rescued by Gabriel (SPN) and Crowley (both). Set post SPN 5x22 and the second Apocalypse. Includes Gabriel/Aziraphale/Crowley pairing. Includes so far:
Remnants of an Old War
A Heaven for Fallen Archangels (companion piece and slight prequel to Remnants)

Teashop Rendez-vous
Once-off fic set a few years after Good Omens, involving an archangel on the run, agent!Aziraphale, protective!Adam and panicky!Crowley. And a teashop.

Shadow Play
A very strange piece, rated R, between SPN Crowley and Aziraphale/Crowley(GO). Set in Hell, including Crowley/Aziraphale/Crowley.
And sequels: Forfeit of a Kiss
Crowley and Aziraphale's first hours back on Earth
Julie's Young Men
When Hell catches back up with them

The Judicious Interpretation of Orders
Aziraphale, Crowley and a very hungover Gabriel. New 'verse.


Collaborations with other authors:

Ironies Timestamps
My fics set in mia6363's and morganoconner's Ironies verse. Basically adding Aziraphale and Crowley from Good Omens into the mix. Includes (so far):
Lizard-eyes and the Angel
A Little Rebellion
Secret Garden
Blessing


Good Omens Fic, NO SPN AT ALL
Which technically shouldn't be on this list, but I got reminded of them recently, and this seemed as good a place to put them as any -_-;

One Minute, At The Last
Judgement Day fic, and the final judgement of our favourite angel&demon. Crowley/Aziraphale, as I appear to have an OTP

Moment of Peace
Crowley and Aziraphale during the London Blitz. More gen/friendship than anything else, and two very tired agents.

Feathers
Very old ficlet, just a tiny A/C moment.

The Blue-Eyed Sorcerer and the Djinn
Aziraphale and Crowley at the time of One Thousand and One Nights. A very twisted version of the Aladdin story ...
Part I

Tremors
Random H/C ficlet, set somewhere pre-book. A/C

Five Meetings (Steps in the Fall and Rise to Grace)
A Good Omens Noir AU. Ensemble Cast, Crowley POV
City of Angels
Concept sketch for the above Noir AU

Paris, 1832
Les Miserables crossover. Aziraphale, Crowley, Javert. Spoilers Les Mis

Softly Slipping
Just a quiet, intense little A/C moment

Into The Grey
Strange thing. A very quiet ending of the world

Breaking
Another strange ficlet. Crowley on Aziraphale's wings

Not Quite the Usual Scene
Cracky ficlet. The last scene of the last battle doesn't go quite as anyone expected

Angel, will you walk into Hell for me?
An angel and a demon, at the end. I ... am not quite sure what to think of this one

Dead Tomes
Cracky prompt ficlet, crossover with the Cthulhu mythos. Aziraphale hunts for the Necronomicon across the centuries

Wheel'n'Deal
Crossover with Dresden Files. What happens when a bunch of cultists trap Anthony J. Crowley and Harry Dresden in the same summoning circle?

Small Temptations
Little prompt ficlet. How to make a proper cup of tea, and why Aziraphale sometimes ... doesn't


*tilts head* Hmm. Think that's all for now?