From a page move: This is a redirect from a page that has been moved (renamed). This page was kept as a redirect to avoid breaking links, both internal and external, that may have been made to the old page name.
To a help page: This is a redirect from any page inside or outside of help namespace to a page in that namespace.
The above category link leads to a list of redirects from inside help namespace. For redirects from outside help space, see Category:Redirects to help namespace.
From a short name: This is a redirect from a title that is a shortened form of a person's full name, a book title, or other more complete article title.
Use this rcat (not {{R from initialism}}) to tag redirects that are the initials of a person's name.