This page in a nutshell: Listed below are various tools intended to simplify and increase efficiency of editing, and provide additional functionality to Wikipedians.
Alternative browsing, alternatives to accessing Wikipedia through your web browser (mobile devices, desktop integration, alternate portals, etc.)
User scripts, a collection of JavaScript routines that add functionality to Wikipedia pages (e.g., regex search and replace, changing article formatting, and simplifying common tasks)
WatchlistBot is a bot that delivers realtime alerts via instant message (XMPP) when watched articles are edited or when watched users or IP networks edit.
Navigation shortcuts offer the ability to add personal links to the sidebar, providing quick and easy access to favourite articles within Wikipedia.
Finding duplicated references: a tool that will find references with the same URL on a page, with some false positives and missed items, is the URL Extractor For Web Pages and Text. It is not a Wikipedia tool, and there may be other tools available for the purpose. Instructions on its use for Wikipedia are in WP:DUPREF. Such references can often usefully be merged, using <ref name= xxx/> for all except one.
Mirrors of Wikimedia content can be filtered from Google search result pages in Firefox using the CustomizeGoogle extension.[1] See meta:Mirror filter for instructions and a filter list.
Wikipedia:Wiki2VCS, script that loads histories onto one's computer, so that they can be quickly diffed and searched
XTools Page History Page statistics and visualization, provides sortable and exportable list of all contributors with number of edits and amount of added text. Provides also results of syntax and grammar checks and latest assessment history.
Finding the responsible user
WikiBlame, searches for given text in versions of article
whoCOLOR, browser script for Grease/Tampermonkey, highlights original authors directly in the article, gets data from a publicly accessible API
XTools Blame, find edits that added the given wikitext
Who Wrote That?, browser extension for Chrome and Firefox, shows editor information for text as use moves mouse over article text.
Editor Interaction Analyzer compares the edits of two to three specified editors to see which articles overlap, sorted by minimum time between edits by both users. Only works on the English Wikipedia. Speed: slow.
Intersect Contribs, compares the edits of two to eight editors at any WMF wiki to see which articles overlap. Speed: fast.
Intertwined contributions, merges the contributions of two editors at any WMF wiki into a single list. Speed: fast. (Currently not working: error connecting to database.)
Interaction Timeline a chronological history of two users' across pages where they both made edits.
MediaWiki Table Utility or this updated version This class constructs a MediaWiki-format table from an Excel/GoogleDoc copy&paste. It provides a variety of methods to modify the style. It defaults to a Wikipedia styling with first column header.[2]
de:Benutzer:Duesentrieb/csv2wp (en) or CSV Converter: Converts many types of spreadsheet tables, including CSV, tab-separated, etc., to MediaWiki or HTML
csv2other: a free open source tool, in .net, to convert CSV and EXCEL files to wiki table format
OpenOffice/LibreOffice
LibreOffice Writer is free. It can open almost any file format. It can export to Mediawiki: File menu > export > save as type > MediaWiki. It will save the file as a .txt file which can be opened with any text editor. Copy the wiki code from the text file. You can save any web page as an HTML file, and then open it in LibreOffice Writer. Edit as needed. Remove the parts you don't want. Keep only tables for example. Then export to MediaWiki. Tables can be further edited in LibreOffice Calc. See: Commons:Convert tables and charts to wiki code or image files. And: Help:Table and the section on spreadsheets and the Visual Editor.
HTML
Html2Wiki is an extension for MediaWiki that imports HTML
Not English, tools that have not yet been translated completely into English. Some need their descriptions translated from German, others are not available in English. Help translate if you can!
Note: Checkinks is buggy use with caution. Consider using instead Internet Archive Bot which can be found in the History tab of any page: "Fix dead links" – login does not require a password.
WikiBiff, To alert users when they have new messages waiting on their talk pages
For a listing of current collaborations, tasks, and news, see the Community portal. For a listing of ongoing discussions and current requests, see the Dashboard.