You have to know there are three amazing places where you can find fanfictions about this pairing :

LJ - AO3 - AFF

And I recommend two places in LJ and AFF filled with amazing fanfictions :

In order to help you discover all those great authors, I'm going to make a list that isn't a list of my personal favorite fanfictions, but just well-written, decent stories that I think deserve to be read. I'll be totally neutral about them, thus you won't be bothered by my opinions n_n
ok, I may be a little biased because many are written by my friends

They are all different, and I'm sure I'm missing/forgetting a lot of great fanfics. Those are just a few of what you can find. I obviously can't put them all in this list, so I hope you won't be upset if you don't find yours here. I want you to know, dear Kyusung writer, that you're doing a great job whatever you write and I'm really thankful and I love you ♥

This list is mostly focused on "old" fanfics, probably because I didn't  have time to read recently. I tried to vary authors, genres and ratings. Will be updated ~

A Slow Kind of Quiet by m1b1n
school AU | romance, fluff | R | 9,500w

Awkward by inmydreams
SJ-verse | romance | G

and when it all falls apart (we should build it back up) by m1b1n
SJ-verse | romance, angst | NC-17 (top!Kyu) | 12,500w

Animal Magnetism by char-isa-pirate
SJ-verse | smut | NC-17 (top!Kyu, top!Ye) | 2,800w

Apple of My Eye by kotahcola
SJ-verse | romance | PG-13 | 6,500w

Backstage by ladye_black
SJ-verse | smut | NC-17 | 900w

Begin at the Beginning by carmine_pink
SJ-verse | romance | PG-13 | 2,900w

Between Us by blueicecreamxo
SJ-verse | romance, humor | PG-13 | with Minwook

boredom by marshmallowtea
SJ-verse | smut | R

Cell phones are the latest invention in rudeness by lyuna
SJ-verse | smut | NC-17 (top!Ye) | 1,300w

Cho Kyuhyun by static_abyss
late 1800s AU | angst | NC-17 | 4,000w

Colors in a Monochrome by prom15e_10ve
sci-fi AU | romance | PG | 6,000w

Crossing Paths by thundersquall
AU | romance | PG-13 | 2,600w

Cruelty by kyusung_addict
SJ-verse | romance | PG

Distractions by deemonic
SJ-verse | smut, humor | NC-17 (top!Ye) | 3,900w

Ever by ricetard
AU | romance, fluff | G | 5,900w

fighting you by rubyls
SJ-verse | romance | PG-13

Find me, Birthday boy by littlemenomaru
SJ-verse | romance | PG

Find you in hell (or here) by ricetard
zombie AU | romance, humor | PG-13 | 5,400w

Freedom Isn't Really Free At All by insanityplays
SJ-verse | angst | R (top!Ye) | 3,000w

Going Home by static_abyss
SJ-verse | bandfic | PG

Greener Grass (the other side ain't so great) by ricetard
AU | humor, smut | NC-17 (top!Kyu) | 5,000w

Heartstrings by turtleclouds
SJ-verse | romance (?) | PG

Hey! I'm Mr. Simple by heartl0ck
SJ-verse | crack, fluff | R | 967w

Holding Hearts by pancakes1004
SJ-verse | romance, angst | PG

It starts at the door by m1b1n
SJ-verse (I suppose) | smut | NC-17 | 1,300w

jewel by rubyls
SJ-verse | crack, fluff | PG-13 | 600w

Last Christmas (I Gave You My Heart) by carmine_pink
SJ-verse | romance | PG | 791w

Leap of Faith (tell me you love me?) by tarmenel
SJ-verse | angst, romance, smut | R (top!Ye) | 8,100w

Lesson Learned by midorihaven
AU | fluff | PG | 2,000w

Let the rain fall by lixia84
AU | romance, smut | R (mostly top!Ye) | 9,000w

Lets go all the way tonight, No regrets... by virgo-phuque
AU | smut, romance, angst | NC-17 (top!Kyu) | 7,000w

Love Me by rhenny
AU | romance | G

Malaise by turtleclouds
dystopia AU | angst | PG

Message in a Bottle by amalious
AU | romance, angst | R (top!Kyu) | with Eunhae, locked from chapter 5

Morphing Memories by rssj1314
AU | angst | PG-13

My Gift to You by midnight
SJ-verse | romance, fluff | PG | 34,200w

Natural Science 1 by rhenny
AU | romance, fluff, humor | PG-13 | 7,000w

Never Again by sujulovenl
AU | angst, fantasy | PG-13 | 11,900w

Night Bathroom Trips by andersenmom
AU | humor | R

Nights of Sharpened Light by maudlinsky
AU | angst | PG-13 | 1,000w

No Words Needed by midnight
SJ-verse | romance (?) | G | 6,000w

Of Clueless Idiots and Borderline Stalkers by phoenix-soar
AU | romance, humor, fluff | PG-13 | 15,000w

Once Upon a Time - Into the Woods by turtleclouds
fairytale AU | romance | PG-13 | with Minwook

Our First Date by midnight
SJ-verse | romance, fluff | PG

Our lines intersect by static_abyss
SJ-verse | romance, angst | PG-13 | 2,500w

Proving Maturity by quinnsan 
SJ-verse | fluff, humor | PG-13

Que Sera Sera by hamishseverin
medieval times AU | romance, humor, fantasy | R

Ringing in My Ears by ficcy
SJ-verse | smut | NC-17 (top!Kyu)

romance is dead by rubyls
SJ-verse | crack, smut | NC-17

roses by jesstoast
SJ-verse | romance | PG | 1,200w

Scents of the Sea by turtleclouds
SJ-verse | romance, fantasy | NC-17 (top!Ye)

Sit at my table by static_abyss
AU | slice of life | PG | 3,000w

Six Reasons Why Kyuhyun Does Not Write Song Lyrics by cairistiona
SJ-verse | crack | PG-15 | with Qmi

Songs of Midnight by nisakomi
SJ-verse | romance, angst | PG-13 | 2,500w

Speechless by phoenix-soar
SJ-verse | romance, fluff | PG-13

Starlight is Falling by turtleclouds
SJ-verse | romance, fluff | PG

Status Quo by turtleclouds
SJ-verse | romance | PG

Steps to falling in love by miss2l
AU | romance, fluff | PG-13 | 11,500w

Stranger Under My Roof by phoenix-soar
SJ-verse | angst, fluff | PG-13

The Definition of Truly Living by sujulovenl
AU | angst | R | 13,000w

The Emergence of Fears by midnight
SJ-verse | romance, angst, fluff | R | 85,000w

The Ever-Changing Definition by theriverrunsred
SJ-verse | romance | PG

the hairy one by ricetard
fairytale AU | humor, romance | PG-13 | 3,400w

The Journey East by lixia84
AU | romance, angst | NC-17 (top!Ye, top!Kyu) | 33,000w

The Man with Black Tears by nytslyer03
AU | angst, romance | PG

the new york state of mind by paralyzing_time
AU | romance | R (top!Ye) | 4,000w

the unwinding parallel by ricetard
SJ-verse | romance | PG-13 | 4,300w

This fic does not deserve a title by shieldkitten
AU | humor | NC-17 | 600w

Tomorrow, Honest! by k19a2i8m1
SJ-verse | fluff, romance | PG-13

Virtual Pink Sparkling Hearts by kpoppin
AU | romance | PG

Voice Within The Noise by kendayawind
AU | angst, romance | PG

What I want to say the next time we meet by thursday
SJ-verse | angst, romance | R

What Once Was by rssj1314
AU | romance | NC-17 (top!Kyu)

What they do behind Closed Doors by deemonic
AU | humor, smut | NC-17 (top!Ye)

When the Late Bell Rings by violettvendetta
school AU | smut, romance | NC-17 (top!Kyu)

Where Warmth Rests by ricetard
AU | romance | G | 3,200w

Where We Went Wrong by ricetard
SJ-verse | angst, romance | NC-17 (top!Kyu) | 36,000w

Whichever Way You Go I'll Be Easy To Find by carmine_pink
SJ-verse | romance (?) | PG-13 | 2,400w

信仰 (Faith) by xdespondence
SJ-verse | romance, angst | NC-17 | with Yewook | 12,000w

Thanks to all the Kyusung writers in existence  ^___^