Beneath the Sandglass by Artemis Rayne
"What looked like a simple suicide takes a turn for the worst when a disturbing pattern crops up across Haven, pitting Audrey and Nathan against the Troubles once more." Slightly AU from the finale, but a very solid case fic (so rare!) with a strong dose of canon and some Audrey/Nathan.

Flicking Switches by Shane Vansen
Lovely slow Audrey/Nathan fic. AU from Season 2.

Forever Within My Numbered Days by Queen Gwenyvere
Very alternate ending to third season, logical and well-reasoned. The ending is emotionally cool, but plot-wise unsatisfactory, to some extent; I'm looking forward to the sequel like whoa.

Hereafter by vega rin
Dark, almost heartbreaking, tangled timeline AU. I kept thinking I could do a better summary, but the author's is best: "Nathan waits."

Over the Way by Lee Tennant
Oddly entertaining AU post-season 1; two FBI agents come to Haven to arrest Duke Crocker, who has vanished. But Haven PD is VERY helpful.... The outsider POV works very nicely, particularly once you figure out what going on behind their backs. Link fixed

Welcome to Haven 2037 by December21st
"He's betting that Audrey ... no, what was it, Emma's editor bears a striking resemblance to someone who was calling himself Agent Howard the first time Duke met him. Duke would respect the guy if Audrey hadn't shown up to dinner alone. But the bastard had promised." Excellent future-fic.