there is no directory according to file type as it is, as it depends on what kind of file it is.
If it's a ship, station or any object map, it should go into /data/maps folder
if it's an actually ship, station or any object Model, it should go into /data/models
Take note that with recent builds, you will also have a second folder /data/cache that will store the generated .ibx files for your models.
If it's an effect map, like an explosion or nebula background it goes into /data/effects
If it's a music file, then it should go into /data/music
If it's a sound folder, it should go into one of the folders in data/sound depending on the properties of the sound file. Someone else will have to explain this to you as I am not too familiar with it.
all tables, irregardless of what property they refer to (music, sound, asteroids, even maps and armor or ships) go into /data/tables
Not too sure about hte command briefing anims tho....