Anamon

DxWnd is one of my go-to examples of an unassuming but impressive piece of open-source software. Started simply by someone wanting to be able to play fullscreen games in a window, today it's an incredibly feature-rich secret weapon to get older games to run on newer versions of Windows at all. Activate "Extended mode" and you'll be battered with four rows of tabs, most of which containing dozens of options. And I love it! This is how functional power-user software is supposed to be. Not trying...