Board Thread:General Discussion/@comment-25523075-20150812171427/@comment-24473195-20150812222522

Fewfre wrote: mw.config.get("wgAvailableSkins"); Just go to the javascript console for the wiki and enter that. should return an array of all skins. source: mw:Manual:Interface/JavaScript

Edit: This is in response to your original question; I personally have no knowledge of any uses on wikia besides monobook, oasis, and wikiamobile. Most if not all those skins available through that table are actually working. One could theoretically force a wiki to use them using javascript. Although that may or may not be against the TOU.

Edit:

In some cases they may be artefacts from when wikia merged with or bought other wiki farms.