Support pages
Below is a list of the donation "support pages" hosted here on donatewiki. Red links are pages that don't exist yet, but we don't necessarily need to create them all. Note that we have a limited set of supported languages now. Adding any new languages should be discussed to see if we can actually support and maintain them (the old foundationwiki pages had more languages but lots of very outdated pages).
Most pages use the base templates {{Support Page}} and {{Support Page end}} for their main styling and layout. They also load the javascript at MediaWiki:SupportPage.js (via a hook in MediaWiki:Common.js).
One other useful template used is {{LocalPage}} which will check if a page exists in a given language, and if not fall back to English. That way you can add links to support pages that might be translated at a later date.
If you have an account here and are logged in, there will be links at the very bottom of each page to edit the current page, edit its template, or view this index. If you spot any issues you can't fix yourself, please file a Phabricator task tagged with #donate.wikimedia.org.
See also the general donatewiki documentation on collab (private)
Thank You pages
As of August 2020 the Thank You pages have moved to https://thankyou.wikipedia.org/. See that link for documentation.