There are so many. Someone posted a really good list on Tumblr the other day. Those are the kind of fanfictions you have to read. I suggest you to check that list out -> http://yune02.tumblr.com/1001fanfictions
Also, OhLittleSparrow on YouTube posts fanfiction recommendations. Just search for "Klaine fanfiction recommendations" and you'll probably find her videos.
The ones that I really love(d) are Go Your Own Way, The Sidhe, Where There's Smoke, Swing Sets and Sandboxes and Dalton.
Hi I ship Klaine and am COMPLETELY in love with Chris so I know loads of Klaine fics. There are loads of drabbles and oneshots for Klaine so if you search glee fanfiction LOADS of them should come up.
The best Klaine story EVER is Dalton by C P Coulter. I really think it changed my life ... :)
Some other really good ones are:
Silence is Golden by KlaineXD
Summer with the Warblers by CrissChrisR5Gleekkk
Gamer Boy by Softlove808
The Andersons PA by inkinthepageandonmyheart
I spy by colourlesscolour
Spanish is Sexy by eloquentfever
Accidentally in love by KurtcoBlainer
My missing puzzle piece by Ticklemedoughface
I know loads more and I might post some of them later ... But seriously read the fqcebool ones they are AMAZING and definitely read Dalton - it's the best one ever!
I think someone should make a FanFiction story of the futuristic Glee. Will continues to work as the Glee teacher and Emma does the same for counseling. The kids who are in this season of Glee should be the previous Glee Kids' children. Like so...
Puck+Quinn=Beth (Yes,The One And Only Beth)
Artie+Brittany=Jackson (I Wanted to add this couple)
Something like that. Lots of drama like,Beth figuring out her real parents,Melody's father isn't actually Finn,or stuff like that... SOMEONE MAKE ONE