Refactoring

Refactoring and Design Patternsrefactoring.guru

Explains design patterns and the scenarios of when they're needed.

Design Patterns and Refactoringsourcemaking.com

An older version of Refactoring.Guru. Has an extra sections on AntiPatterns.

Refactoring UIadamwathan

Twitter curated feed of UI dos and don'ts as images.

Explore, Learn, and Master Industry-Standard PatternsJava Design Patterns

Typical considerations software engineers should think about when writing code.