An FC is a Full Combo on guitar hero or rock band, it means 100% without losing your note streak the entire song.
I play guitar, expert

Rock Band 1 Songs
Black Hole Sun
Detroit Rock City
(Don't Fear) The Reaper
Gimme Shelter
I Think I'm Paranoid
In Bloom
Learn to Fly
Maps
Mississippi Queen
Say It Ain't So
Tom Sawyer
When You Were Young
Songs About To FC In Rock Band 1
Wanted Dead or Alive
Should I Stay or Should I Go
Welcome Home
Plenty of other songs in this game I can FC, but don't ever play, i can fc most of this game

Rock Band 2 FCs
Alabama Getaway
Bad Reputation
Cool for Cats
Feel the Pain
Float On
Go Your Own Way
Hungry Like the Wolf
Livin' on a Prayer
New Kid in School
One Step Closer
Pretend We're Dead
Ramblin' Man
Today
Songs About To FC In Rock Band 2
Carry on Wayward Son
The Middle
Also, a TON of songs here i can FC, or maybe already have, but can't remember, because they are so easy, i'll look through them soon, so i can get this list full of everything I have FCd.

Rock Band 2 DLC
Dirty Little Secret
Charliene (I'm Right Behind You}
Still Alive
Street of Dreams
Don't Stop Believing (this and street of dreams may be my 2 best FCs ever, look them up)
RB 2 DLC I am Working on FCing
Indestructible
Dr. Feelgood
Saints of Los Angeles