Modelling

Behavioral

Activity Diagram:  the flow of operations in an activity
Communication Diagram :  the interaction between objects
Interaction Diagram :overview   sequences and activities
Sequence Diagram :  the interaction between objects
State machine  : how the state of objects changes after events
Timing  Diagram : the behavior of objects in a period of time
Use case  Diagram : what actors perform which action in the system

Structual :

Class Diagram : classes, interfaces, and relationships within a system
Component Diagram :  components and their dependencies
Composite structure Diagram :    the internal structure of a class
Deployment  Diagram :  how components are mapped to hardware resources
Object Diagram :   a view of the system at a particular time
Package Diagram :  how classes are split into logically related groups