How to query all posts from all custom post type

Try it with this in your theme’s functions.php:

add_action( 'pre_get_posts', 'post_type_home_query' );
function post_type_home_query( $query ) {
	/* not an admin page and is it's the main query */
	if ( !is_admin() && $query->is_main_query() ) {
		if ( is_home() ) {
			$args=array(
				'public'   => true,
				'_builtin' => false
			);
			$post_types = get_post_types( $args, 'names', 'and' );
			if ( !empty( $post_types ) )
				$query->set( 'post_type', array_keys( $post_types ) );
		}

	}
}