IObit Uninstaller is a free uninstaller for Windows. Obviously, uninstallers are nothing new. There are a billion third-party uninstallers available, and Windows has its own built-in uninstaller.
I chose to include IObit Uninstaller here because it doesn't focus squarely on applications as some uninstallers do. The program has an entire tab dedicated to browser toolbars and plug-ins. In the case of Internet Explorer, the software can also remove ActiveX controls.