Exactly a year ago today, we had 55 usable skins for MediaWiki . Now, we have a much more healthy 79. There are >= 23 skins that used to work with MediaWiki that no longer do. This week 5 skins were added thanks to https://www.mediawiki.org/wiki/Skin:Bluelib
being added to MediaWiki.org ! All usable skins are all showcased on https://skins.wmflabs.org
I believe that the more skins MediaWiki supports, the more vibrant our ecosystem can be for developers and end-users. I dream of a world where not every MediaWiki instance looks like an instance of Wikipedia.
In 2022, the work being done on https://mediawiki.org/wiki/Desktop_improvements
will see the number of usable skins rise to at least 80 skins and I am personally exploring a script that converts WordPress themes  into MediaWiki skins that should add another 10 skins at least (Feel free to message me offline if you want to talk more about this ).
However, there is still much work to be done if we want to have a healthy skin ecosystem!
* 13 of these 79 skins are throwing deprecation warnings, meaning they may break in future MediaWiki versions . Please help get those patched!
* Fix an unstable skin! We have 9 skins that do not work on the current MediaWiki master. Can you help fix one of them? 
* Make a new skin! Skin development has changed a lot in the last 2 years. It is more constrained and does not require knowledge of PHP. Take our documentation  for a spin and see if you can create one and let us know where the documentation can be improved and the limitations that you ran into with the platform while building them . Check out the online skin builder tool if you haven't already. 
* Improve the mediawiki.org
documentation! Add screenshots, add links, translate a skin.. anything that might help someone use a skin.
* Write a patch to help improve the core skin architecture where a patch is welcome 
Wishing everyone a happy holiday and happy skin-building.
Only skins now that cannot be previewerd