The Modifiers menu provides a way to apply frequently used modifiers quickly.
The availability of items on this menu depends on the current selection. If a modifier doesn't apply to currently selected objects, it is unavailable in the menu.
Edit/Convert 
Selection 
Spline 
Geometry (Convert to Mesh) 
Geometry (Parametric) 
Free Form Deformers 
Confom 
NURBS 
Patch 
Animation 
Cloth 
Hair and Fur 
Simulation 
Cameras 
Subdivision Surfaces 
UVs, Maps and Materials 