This is list is from the classic "Design Patterns: Elements of Reusable Object-Oriented Software" by Gamma, Helm, Johnson and Vlissides.

Creational:

1. Abstract Factory - families of product objects

2. Builder - how a composite object gets created

3. Factory Method - subclass of object that is instantiated

4. Prototype - class of object that is instantiated

5. Singleton - the sole instance of a class

Structural:

1. Adapter - interface to an object

2. Bridge - implementation of an object

3. Composite - structure and composition of an object

4. Decorator - responsibilities of an object without subsclassing

5. Facade - interface to a subsystem

6. Flyweight - storage costs of objects

7. Proxy - how an object is accessed; its location

Behavorial:

1. Chain of Responsibility - object that can fulfill a request

2. Command - when and how a request is fulfilled

3. Interpretor - grammar and interpretation of a language

4. Iterator - how an aggregate's elements are accessed, traversed.

5. Mediator - how and which objects interact with each other

6. Memento - what private information is stored outside an object, and when

7. Observer - number of objects that depend on another object, how the dependent objects stay up-to-date

8. State - states of an object

9. Strategy - an algorithm

10. Template Method - steps of an algorithm

11. Visitor - operations that can be applied to object(s) without changing their classes