Behavioral design pattern

This design pattern is all about algorithms and assigning object responsibilities. This design pattern also helps design communications between different classes and objects and their interconnections. While behavorial-class patterns use inheritance to distribute behavior between classes, behavorial-object patterns use object composition to perform the same task.
Covering some patterns under it :

Memento Pattern
Mediator Pattern
Observer Pattern
Null Object Pattern
Visitor Pattern
Interpreter Pattern
Iterator Pattern
Strategy Pattern
Command Pattern
Template Method Pattern
Chain of Responsibility Pattern