Nukular Tools
The nukular tools (mirror here) can be used for helping you with creating new songs for Frets on Fire.
Freetar Hero SNG to Frets on Fire MID converter
Self-explanatory. If you have .sng files from Freetar Hero and you want to convert them into .mid files for Frets on Fire, use this tool.
Frets on Fire MID Note Shifter
If all of the notes in your .mid file are out of place by some time, use this tool to move all of them forwards or backwards in time by the same value.
Frets on Fire Skill Changer
Is your Easy song labeled as Amazing? Is your Medium Song labeled as Supaeasy? If you want to fix it, use it.
Frets on Fire Track Duplicator
If you have only one difficulty, marked for example as Medium, and want to have the same notes for the Amazing difficulty, make use of this thing.