I'll try not to repeat, but massive +1s for 'Ask No Questions, Hear No Lines', 'Family is (mostly) for children', 'The right thing in the wrong way' and 'Flames We Never Lit'. Generally, igrockspock, roboticonography and irnan are good bets for this type of stuff.
New recs!
Pepper Potts
Unscheduled Meetings (http://archiveofourown.org/works/244316) and Accountability (http://archiveofourown.org/works/181451/chapters/266906), both by roboticonography. Pepper before IM1, and after IM1 respectively (10k/13k words). Competent and confident Pepper, with a really spot-on voice and in-character interactions with Tony.
One Hundred and Five Percent (http://archiveofourown.org/works/1062796) by IamShadow21 Adorable and hot coda to IM3 featuring Techopath!Pepper a la comics!Extremis.
Rescue 'Verse (http://archiveofourown.org/series/47220) by jumpfall (22k words) Post-IM3 Pepper gets a suit, adjusts to being a superhero, and is awesome.
Between the Darkness and the Stage (http://archiveofourown.org/works/542907) by marinarusalka Pepper rescues Tony when he's kidnapped between IM1 and IM2. Features Pepper being the strong one in multiple ways.
Natasha Romanoff
A bunch of short team-focused fics. Congratulations on an Excellent Kill (http://archiveofourown.org/works/627351) by igrockspock A Different Glow for Every Window (http://archiveofourown.org/works/485157) by winterhill Fellowship (http://archiveofourown.org/works/492601) by irnan Progress Reports, Pancakes, and Paper Planes (http://archiveofourown.org/works/431317) by such_heights
Darcy Lewis
Shorts (both Darcy/Sif, so two for the price of one on these! Both are cute): A Girl Worth Fighting For (http://archiveofourown.org/works/450317) by beardsley Scavenger Hunting is Extremely Likely Disasterous (S.H.I.E.L.D.) (http://archiveofourown.org/works/395438) by amathela
Longer fics: Life After You've Been Disappeared (http://archiveofourown.org/works/748641) by snack_size (50k words) Darcy-joins-SHIELD fic. This is the best fic I've read of this trope, keeping everyone involved believable, and has a solid actiony plot. Features the beginning of a Steve/Darcy relationship, but nothing explicit.
We'll Run Like We're Awesome (http://archiveofourown.org/series/57783) by themonkeycabal. (100k+ words) Darcy-is-Tony's-Biological-Daughter!AU. Again, a strong execution of a common trope. Covers Darcy from a fairly young child to the events of The Avengers.
no subject
New recs!
Pepper Potts
Unscheduled Meetings (http://archiveofourown.org/works/244316) and Accountability (http://archiveofourown.org/works/181451/chapters/266906), both by roboticonography.
Pepper before IM1, and after IM1 respectively (10k/13k words). Competent and confident Pepper, with a really spot-on voice and in-character interactions with Tony.
One Hundred and Five Percent (http://archiveofourown.org/works/1062796) by IamShadow21
Adorable and hot coda to IM3 featuring Techopath!Pepper a la comics!Extremis.
Rescue 'Verse (http://archiveofourown.org/series/47220) by jumpfall (22k words)
Post-IM3 Pepper gets a suit, adjusts to being a superhero, and is awesome.
Between the Darkness and the Stage (http://archiveofourown.org/works/542907) by marinarusalka
Pepper rescues Tony when he's kidnapped between IM1 and IM2. Features Pepper being the strong one in multiple ways.
Natasha Romanoff
A bunch of short team-focused fics.
Congratulations on an Excellent Kill (http://archiveofourown.org/works/627351) by igrockspock
A Different Glow for Every Window (http://archiveofourown.org/works/485157) by winterhill
Fellowship (http://archiveofourown.org/works/492601) by irnan
Progress Reports, Pancakes, and Paper Planes (http://archiveofourown.org/works/431317) by such_heights
Darcy Lewis
Shorts (both Darcy/Sif, so two for the price of one on these! Both are cute):
A Girl Worth Fighting For (http://archiveofourown.org/works/450317) by beardsley
Scavenger Hunting is Extremely Likely Disasterous (S.H.I.E.L.D.) (http://archiveofourown.org/works/395438) by amathela
Longer fics:
Life After You've Been Disappeared (http://archiveofourown.org/works/748641) by snack_size (50k words)
Darcy-joins-SHIELD fic. This is the best fic I've read of this trope, keeping everyone involved believable, and has a solid actiony plot. Features the beginning of a Steve/Darcy relationship, but nothing explicit.
We'll Run Like We're Awesome (http://archiveofourown.org/series/57783) by themonkeycabal. (100k+ words)
Darcy-is-Tony's-Biological-Daughter!AU. Again, a strong execution of a common trope. Covers Darcy from a fairly young child to the events of The Avengers.