ACQUA: StackExchange best answer predictor
G. Gkotsis, K. Stepanyan, C. Pedrinaci, J. Domingue, and M. Liakata. It's all in the Content: State of the art Best Answer Prediction based on Discretisation of Shallow Linguistic Features. In Proceedings of the 2014 ACM Conference on Web Science, WebSci '14, pages 202-210, New York, NY, USA, 2014. ACM.
Auto-Add A Comment When Closing
Automatically adds a comment with details of the close reason, so that the OP can see why their question may be being downvoted, and improve it, before it is closed (disabled for Duplicate, Off-topic > Migrate, and Off-topic > Other)
Remove Stackoverflow Sidebar
Remove the sidebar and stretch the main content so that it fills the whole width, better when you have a browser window open next to your code and it's too narrow to see much with all the wasted space.
Remove User ID from Stack Overflow Share URLs
Removes the User ID from the URL displayed by the "Share" button for questions and answers on Stack Overflow and related sites. For a description of why the User ID was added, see https://meta.stackoverflow.com/q/277769
StackExchange hide closed questions
Hide closed questions on the home page and in other lists of questions. Put a link showing the number of closed questions that have been hidden that shows the closed questions again.