I had a chance to revisited object oriented design patterns recently. I found a couple online tutorials and watched through them. I highly recommend the Tuts video: https://code.tutsplus.com/courses/php-design-patterns and the Source Making website.
It’s amazing how every single time I revisit design patterns, I discover something new. You can visit my notes for this session of design patterns on my Github page where I go into super detail on each of the popular design patterns from both tutorials above. I hope you find it useful!