The sad thing about me is, I only read Fluttershy fanfics. I personally think that's a bad thing because there is probably tons and tons of other fanfics out there and for only reading fics based on one character, it really limits my world. (Although I have read Cupcakes, My Little Dashie, and am currently reading Cheerilee's garden). But, hopefully I will read more fics out there in the future.
My favorite (Fluttershy) fics are "A rose is a rose" & "My sister Fluttershy".
Rose is a rose is one where I read throughout the days in sixth grade, and I still remember exactly the experiences I felt of adventure in it. It gets everyone's personality (Back in 2012) very accurate. It was the first time I was actually excited to read something.
My sister Fluttershy is currently, the only thing on MLP that I actually cried about for a short time (literally). It focuses more on Fluttershy's fan made older sister, and I could really feel the atmosphere in it. Now that I've heard Fluttershy is going to have a little something in the future (spoilers), it's going to make this story untrue but, now I feel like reading it again, after 3 years.