Arcath

Supplies filters
Orignal use case was WordPress themes that used images from facebook which in schools was blocked. By proxying the image through wp-camo images from Facebook will now load in school.

WP-Camo

Passes images through the WordPress site to prevent mixed content errors and bypass local filtering.

sleepm

Manage WordPress proxy in one page, you can set some domains that can be accessed through proxy. 
Also, http basic auth support.

WP Proxy

Manage WordPress proxy in one page, you can set some domains that can be accessed through proxy. Also, http basic auth support.

WP-Camo vs WP Proxy