The repository design pattern is a way to abstract the data access logic of an application, allowing the business logic to depend on a simple interface for storing and retrieving data without having to worry about the details of the underlying storage technology. It promotes separation of concerns and can make the code more reusable and testable.

The singleton pattern ensures that a class has only one instance and provides a global access point to it.

The decorator pattern dynamically adds behavior to an object by wrapping it in a decorator object.

The factory pattern defines an interface for creating objects in a super class, but allows subclasses to alter the objects that will be created.

The builder pattern separates the construction of a complex object from its representation, allowing the same construction process to create different representations.

Domain-Driven Design is a software development approach that focuses on modeling the business domain in order to better understand the problem being solved and create a more effective solution.

The SOLID design principles are a set of guidelines for writing maintainable and scalable software.