In the classic versions of Mac OS, if you clicked one application window, that click would bring all of that application’s windows to the front. Apple abandoned that behavior in Mac OS X, changing things so clicking an app’s window would bring only that window to the front. If you want all of an app’s windows to come forward, you have to click the app’s Dock icon. Some utilities, like DragThing, could restore the old behavior, but the advent of macOS 10.15 Catalina and Apple’s elimination of support for 32-bit apps killed them all off.
In Front and Center’s Classic mode, which is the default, a click on one window in an app brings all of that app’s windows to the front. The utility also offers a Modern mode, which provides the default macOS behavior, but invokes the Classic behavior if you hold down the Shift key while clicking a window. Front and Center has optional Dock and menu bar icons, which are on by default.
That’s it! Front and Center is utterly simple, and if it provides the window management behavior you want, it’s well worth the $2.99 price.