Nimbus Digital

Redirects http://somedomain.tld to http://someotherdomain.tld
Assuming you have 2 or more domains in use for a single WordPress site. This plugin forces the use of only one no matter which is entered in the address bar.
If, for some reason, your host won’t automatically redirect from one domain to another, then this plugin will do it. It checks the URL used to access the site and does a 301 redirect if incorrect.
In theory htaccess should do this, but in my case it didn’t. Perhaps because I am using domain aliases (or CNAMEs) and I wanted to insure that the main one was always in use, even when accessed using old links.

Force Domain Redirect

Forces your Wordpress site to load on the domain registered in the WP admin.

Semio Design

Pierre-André Boissinot

When you use the WordPress editor to insert a media in the content field it stores a reference to the absolute path. 
So if you change the location of your site (by switching from staging to production environment for example) all your paths will be incorrect. 
This plugin stores relative pathes in the db instead of an absolute path. 
Beware: this plugin must be activated BEFORE inserting a media into the content field. It has no effect on the medias stored before the activation. 
It’s mostly based on the WP_SITEURL constant which should be defined in the wp_config.php file. If this constant isn’t defined it uses the “siteurl” option value instead. 
If the plugin detects that you access the website from another location than the “siteurl” defined initially it can correct most of the wrong urls in the database.
Localisation of the plugin into french.

Simple Relative Content

This plugin makes all attachments urls stored in database relative to the WP_SITEURL url.

Force Domain Redirect vs Simple Relative Content