Loop over all custom fields of all posts and output.php

// get your custom posts ids as an array
$posts = get_posts(array(
    'post_type'   => 'post',
    'post_status' => 'publish',
    'posts_per_page' => -1,
    'fields' => 'ids',
    )
);
//loop over each post
foreach($posts as $p){
    //get the meta you need form each post
    $my_post_meta = get_post_meta($p);
	foreach($my_post_meta as $key => $value) {
		echo 'post id: ' . $p . '<br />Key: ' . $key . ' - Value: ' . $value[0];
	}
}