Extension:OneColumnAllPages

The OneColumnAllPages extension implements a special page, "Special:OneColumnAllPages", that displays an unformatted list of all pages on the wiki. What's that you say? Special:AllPages and API:AllPages already do something like this? Sort of; Special:AllPages gives you the page titles but puts them in a three-column list. API:AllPages gives them to you in some format like HTML, PHP, JSON, TXT, etc. that you then have to strip out the garbage from. This is designed to just give you an unformatted list with one page title per line, so that you can easily copy and paste all or part of it into, say, Special:DeleteBatch (see Extension:DeleteBatch) if you want to mass-delete stuff, or into your favorite spreadsheet application so you can then play around with it some more (e.g. adding pipes and new page titles so that you can put it into a file that will be fed into moveBatch.php.)

An alternative to using this extension is to set $wgExportFromNamespaces to true so that you can get a list of pages in each namespace by going to Special:Export.