Add scheduling options to WordPress blocks (Gutenberg)
Register the blocks you want to have the scheduling options available by adding block(s) through the javascript filter scheduleBlock.blocksToAddSchedule which should be enqueued in the editor.
wp.hooks.addFilter('scheduleBlock.blocksToAddSchedule', 'my-plugin/namespace', function( blockNames ) {
blockNames.push('core/heading');
blockNames.push('core/image');
// blockNames.push('my-plugin/block-name');
return blockNames;
});