Great! Since you already have a src folder for your block's source code and a build folder for the compiled output, you can easily add a second block within the src folder and include it in the build process.

Here’s how you can proceed:

1. Extend the Folder Structure

Update your current folder structure like this:

src/
├── block-1/
│ ├── block.json
│ ├── edit.js
│ ├── save.js
│ └── style.css
├── block-2/
│ ├── block.json
│ ├── edit.js
│ ├── save.js
│ └── style.css
build/
├── index.js
├── editor.css
├── style.css

2. Create Files for the New Block

Add the files for block-2 in the src/block-2/ folder.

block.json

edit.js

save.js

style.css

3. npm run build

4. Register Both Blocks in PHP

function my_custom_blocks_register_assets() {
wp_register_script(
'my-custom-blocks-editor-script',
plugins_url( 'build/index.js', __FILE__ ),
[ 'wp-blocks', 'wp-element', 'wp-editor' ],
filemtime( plugin_dir_path( __FILE__ ) . 'build/index.js' )
);

wp_register_style(
'my-custom-blocks-style',
plugins_url( 'build/style.css', __FILE__ ),
[],
filemtime( plugin_dir_path( __FILE__ ) . 'build/style.css' )
);

register_block_type( __DIR__ . '/build/block-1' );
register_block_type( __DIR__ . '/build/block-2' );
}
add_action( 'init', 'my_custom_blocks_register_assets' );