I think at least you want:
If you have bottom-mounted components , probably add bPlace, bNames, and bValues.
If you have components that require special drilling/milling, include Holes/Milling as appropriate.
If you have SMT parts, you'll probably want tCream/bCream as appropriate (i think -- i'm not too familiar with SMT parts).
If you've marked areas as restricted, you probably want tRestrict, bRestrict, and vRestrict.
I'm basing the above on my one PCB design and the descriptions of the layers from Build your own Printed Circuit Board by Al Williams.