The Strategy design pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. This allows the algorithm to be selected at runtime.

The Singleton design pattern is used to create a single instance of a class and provide a global point of access to that instance.

The Factory design pattern is used to create objects without specifying the exact class of the object that will be created.

The Prototype design pattern is used to create a new object by copying an existing object.

The Decorator design pattern is used to add new functionality to an existing object without changing its structure.

The Adapter design pattern is used to convert the interface of a class into another interface that a client expects.

The Facade design pattern is used to provide a unified interface to a set of interfaces in a subsystem.

The Abstract Factory design pattern is used to define an interface for creating objects, but lets subclasses decide which class to instantiate.

The Builder design pattern is used to separate the construction of a complex object from its representation so that the same construction process can create different representations.

The Composite design pattern is used to define a set of classes that share a common interface, allowing objects to be composed dynamically.

The Proxy design pattern is used to provide a surrogate or placeholder for another object to control access to it.

The Iterator design pattern is used to provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.

The Mediator design pattern is used to define an object that encapsulates how a set of objects interact.

The Observer design pattern is used to define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

The Command design pattern is used to encapsulate a request as an object, thereby allowing you to parameterize clients with different requests, queue or log requests, and undo requests.