Ascendoor Metadata Manager plugin will display the metadata (metabox data or custom fields data) associated to the particular posts, terms, users and comments (including for custom post types and custom taxonomy terms).
Ascendoor Metadata Manager plugin will list all the metadata with its meta key, meta value and action to delete or edit the meta key and value directly from the backend (edit page). The plugin also provides the settings option (Admin Dashboard > Settings > Ascendoor Metadata Manager) for you to disable/enable the metabox manager for each post types, taxonomies, users and comments section.