Last year Anders Noren tweeted a series of steps he takes when creating a new block theme. The steps have been collected into this article which has interesting information about what is involved in creating a block theme, the workflow and some useful tools.

Creating or customizing block themes – this mini-tutorial shows how to enqueue custom styles for individual core blocks. The styles are only loaded when the block is used. The method is straightforward.

Brian Gardner has launched a new premium theme named Open Letter. It is a minimalist block theme.

The Create Block Theme plugin is a free plugin in the WordPress directory. It lets you create a new block theme, clone an existing one, create a child theme, and save user templates and styles to the active theme. This tutorial shows how to use the various plugin features.

In this video Jamie Marsland shows one of the reasons why it is easier for new users to get started building their site with a Classic theme than a block theme.

In this video we take a deep dive into the current state of WordPress block themes. We look at the most popular ones, we look under the hood to understand block themes, and we look at the current stats. I have a better understanding of block themes after going through this process.

While this article clarifies the differences between Classic, Hybrid, and Block themes, its real value is in the excellent summary of features available for block themes and how to access them.

Block Theme Development – Here is a good article by Bud Kraus on working with theme.json. It covers the order of the cascade, definition of elements, and includes a reference section.

Working with Block Themes – This article by Frank Klein considers the advantages to using a child theme vs forking the theme. The best route is a bit different with block themes than classic themes.