Global custom meta box

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In addition to the other answers, you can further improve it by looping through an array of types instead of manually adding a new add_meta_box() line each time you add a new type.

$postTypes = array( 'custom-post-type1', 'custom-post-type2', 'custom-post-type3' );
foreach( $postTypes as $pt )
    add_meta_box( 'adv_form_box1', 'Advanced Form', 'adv_form1', $pt, 'side', 'high' );