She always knew By Raspberrygirl
Don't Take Life Seriously, It's Not Permanent By Britz
Animorphs (AU The Invasion) By Shane C.
Trust By RaspberryGirl
One Least Likely By Augustine Quill (who last I checked held top # of reviews on ff.net animorphs- that may have changed in the years)
And for crazy, nasty stuff that you'd never admit you read: anything by Jinako-Chan
Sorry it's long, but I couldn't bear to leave one out in the name of brevity
Edit: Of course there's always MY fanfiction (mememe) one of my reviewers said that I have the most Reviews per chapter for animorphs on ff.net. But again, things may have changed.
