On this page, I will include a list of resources about how to create custom block styles and patterns for WordPress blocks.
If you have tips about resources, please email me to add them to the list: hi@wpblockstyles.com
Note that with time, as the development of the block editor continues, some of these code examples and instructions may be outdated.
Articles
Theme shaper: Customizing Gutenberg blocks with block styles Kjell Reigstad on February 15, 2019.
Code.tutsplus.com: Create Style Variations for WordPress Gutenberg Blocks: Part 1 and Create Style Variations for WordPress Gutenberg Blocks: Part 2