ねんでぶろぐ さんの WordPress5.5 ブロックパターンを簡単に登録やメンテナンスできるようにする が とても便利だった

// ブロックパターン追加
$pattern_args = array(
  'post_type'       => [ 'my_block_patterns' ],
  'post_status'     => [ 'publish' ],
  'posts_per_page'  => -1,
);

$pattern = get_posts( $pattern_args );

if( ! empty( $pattern ) ) {

  foreach( $pattern as $value ) {

    $pattern_title = get_the_title( $value->ID );
    if( empty( $pattern_title ) ) {
      $pattern_title = __( 'Untitled block pattern', 'translation' );
    }

    $pattern_content = get_the_content( null, false, $value->ID );

    $pattern_categories = [];
    $block_terms = get_the_terms( $value->ID, 'my_block_category' );
    if( ! empty( $block_terms ) && ! is_wp_error( $block_terms ) ) {
      foreach( $block_terms as $block_term ) {
        $pattern_categories[] = $block_term->slug;
      }
    }

    if( ! empty( $pattern_content ) ) {
      register_block_pattern(
        'jr/block_patterns-' . $value->ID,
        [
          'title'       => $pattern_title,
          'content'     => $pattern_content,
          'categories'  => $pattern_categories,
        ]
      );
    }

  }

}