The full set of fills used in the current ARCHICAD project is available in the Fills Dialog Box (Options > Element Attributes > Fills).
Fills in this pop-up are grouped according to type: Solid, Vectorial, Symbol, Gradient and Image.
You can modify this set manually or by importing items with the Attribute Manager.
Set Fill Availability by Category (Drafting, Cover, Cut)
Use the Availability Panel of the Fills dialog to define one or more categories for each Fill.
See Fill Categories.