Chris Klosowski

Allows you to upload your themes CSS, JavaScript, and Images into your Dropbox ‘Public’ folder and server these files from the Dropbox network, reducing the bandwidth of your server and allowing users to load your site faster. Please note that as of now, this plugin only supports themes who use the filters ‘template_directory’, ‘template_directory_uri’, ‘stylesheet_directory’, and ‘stylesheet_directory_uri’ to determine the paths to the theme’s template and stylesheet files. I would only suggest this plugin for users who aren’t afraid of getting their hands a little diry.
This plugin is in no way affiliated with Dropbox.

Dropbox CDN

Use your Dropbox 'Public' folder as a free Content Delivery Network (or CDN). Please read the full description.

耗子

使用各大CDN厂商提供的API自动清理节点缓存，同时提供前台静态资源公共CDN加速。 
此插件搭配静态缓存插件使用效果更佳。 
插件发布&&使用教程链接：https://hzbk.net/archives/763.html

WP-CDN-Yes – WordPress CDN 插件

好吧，摊牌吧，我是刷好评的，实际上这个插件我也没用过

Dropbox CDN vs WP-CDN-Yes – WordPress CDN 插件