I have read the well-known book: Design Patterns - Elements of Reusable Object-Oriented Software written by the Gang of Four (Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides).
In order to practise efficiently I have developed all the patterns shown in the book in PHP language (programming language used at work). Each pattern is documented and unit tested using PHPUnit. Like the book, it's a catalog of 23 patterns and you should consider it as a basis for learning purposes.
Found a typo? Something wrong with this content? Just let me know and please feel free to contribute!
Have a look at https://phpatterns.readthedocs.io!
The MIT License (read the LICENSE file).