This page contains a list of common IDs and classes, especially when there is important information about what they're intended to be used for, or when there is a (possible) collision.
For a more extended collection of historically grown list of IDs and classes visit Wikipedia's Catalogue of CSS classes.
Comment (edit summary) in history, recent changes, watchlist, ... The parentheses are inside this span.
Diff when comparing revisions.
Around the edit section link next to section headers.
MonoBook, Vector, Moderno
The page title
Holds the page content, including categories, contentSub, ...
Holds everything between the page title and contentSub on the one hand, and ArticleFeedback and categories on the other hand. Present on each page view (includes history view, non-existing pages, print view, ...). Known issue: May contain unrelated elements (bug 35247)