This plugin is really truly just for Google Fonts. In order for the maintainer to deal with other web-based font providers he would have to greatly increase the size of his plugin to deal with the completely separate APIs for each one. Adobe’s Typekit, for example, requires a whole different way of identifying the user and their rights to the fonts available, including a distinction between free and paid fonts, and that becomes more complex than the case with Google where it’s all free and nothing more than a single, simple API key string is needed.
To be honest, Typekit fonts are probably best to serve directly from your site or using custom HTML as recommended by Adobe to pipe them in from a CDN. Perhaps someone would build a similar plugin for easy quick typekit font previewing and prototyping, but I wouldn’t wait for it.
