phpMyAdmin

Tobias Ratschiller wrote it in 1998 and handed it to a community project in 2001. It comes preinstalled on virtually every shared host and in every LAMP bundle: browse tables, edit rows in a form, run arbitrary SQL, import and export dumps, manage users and indexes.

The convenience has a flip side. The tool almost always sits at a guessable path, runs with enough privilege to read the whole database, and is written in PHP with two decades of history behind it — which has made it a perennial target for automated scanning. The standard advice has not changed: move the path, put HTTP auth in front of it, or don't run it in production at all.