Here are my notes I made while reading the book Head First Design Patterns. It has full and quality implementation of every design pattern in the book with notes on different patterns and principles. The examples are written in Kotlin.
The Head First Design Pattern is a great read if you are just starting to learn design patterns.
Check out the Github repo below and do star it if you find it useful: https://github.com/Devansh-Maurya/Design-Patterns-And-Principles