Custom Field Snippet Plugin creates a snippet for displaying Custom Field data.

WordPress has get_post_meta function which displays custom field data. If you have many custom fields, you need many get_post_meta. It might be a hard work.

This plugin creates a snippet, like <?php echo get_post_meta($post->ID,'FIELD NAME HERE',true); ?>. All you have to do is, copy the codes and paste them to your theme.

Additionally, when you are using Advanced Custom Fields plugin, you can get the codes for ACF. When you use conditional logic in your custom fields, you will get the snippets with conditional logic settings.