Metaclasses can be employed to enforce coding standards and best practices across a codebase, automatically checking for common errors or ensuring certain patterns are followed.

Python's metaclasses enable advanced code introspection and dynamic class modification, making them useful for implementing frameworks like SQLAlchemy and unittest.

Metaclasses can be used to create domain-specific languages (DSLs) and build powerful frameworks like Django and Flask.

Python's metaclasses can be used for implementing advanced caching mechanisms or transparent proxy objects, allowing for more efficient code execution.

Metaclasses are also utilized in sophisticated mocking frameworks like Mock or pytest-mock, enabling effective testing of complex code with minimal effort.