camdagr8

This plugin creates a thumbnail list of the available page templates. 
 
Clicking a thumbnail updates the <code>Page Attributes -> Templates</code> drop down to the corresponding page template.

Page Template Thumbnails

This plugin creates a thumbnail list of the available page templates.

Mike Selander

Simple Frontend Template Display will show the name of the template that you’re using in the toolbar when you’re in the frontend of your website. You can use this to keep track of the various templates you’re using without having to hop into the edit screen every time you want to check a template.
All you have to do to get this working is to install the plugin. It will then automatically show up in the toolbar on all pages on your site.

Simple Frontend Template Display

Adds an admin toolbar menu item that displays the current page template.

Page Template Thumbnails vs Simple Frontend Template Display