a2rocklobster

buildcreate

This plugin allows you to sync local and remote media uploads, theme files, and plugins folders with one click via FTP. Do all your development on your localhost, initiate a sync whenever you need to from the FTP Sync options page.
FTP Sync can only be used from your localhost. If you try to use it from your development server you will get a message reminding you that you are not on your localhost. Also, an admin bar link will be on your localhost copy but not on your development server admin bar.
*IMPORTANT: Setup your local site’s wp-config.php to use your remote site’s database. Add your IP address (<a href="http://www.whatismyip.com/" rel="nofollow ugc">What is my IP?</a>) to the “Remote Database Access Hosts” in cPanel so you every time you sync your files even the database will match up with everything (since it’s the same database!).

FTP Sync – Theme, Media & Plugin Files

This plugin allows you to sync local and remote media uploads, theme files, and plugins folders with one click via FTP.

Chris Allen

Poodle Plugins

This plugin makes it easy to distinguish between your local development site, and your live site. 
I created this because I often use a local duplicate of my live site, for development, with the same DB, and the same URL.
I needed a quick & easy way of distinguishing between my live and development sites at a glance. This plugin acheives that in the simplest way possible.
There are settings for colour, positioning and the text displayed on the badge. It is also possible to add a link onto the badge.

WP Dev Flag

Shows a floating badge on the front end, to visually distinguish your development site from production.

FTP Sync – Theme, Media & Plugin Files vs WP Dev Flag