FE7 allows custom battle animation lists for characters by using bytes 0x25 and 0x26 in the character data table. FE8 has the same function in the ROM (which isn’t called), but wouldn’t work very well due to branching promotions. Thus, this hack ports the functionality over while allowing for different lists based on matching class and character id.
Download here, read the readme.
EDIT: Seems FEBuilder already has a patch for this (seems to work the same way), called Character Custom Animation, so this is only useful for buildfile people.