On many Linux desktop environments it is the default - or can be configured: To hold the Windows Key ('meta') and left-mouse-drag a window around from _anywhere inside the window_! No need to get the mouse into the 'title bar'!

Additionally, meta+middle-mouse-drag allows one to resize a window from anywhere in the whole window!! (it chooses the closest corner when the drag starts) and this, being able to resize a window without needing to put the mouse in a usually-very-thin window border, is extremely liberating in my opinion! To the point where I really miss it on sub-windows where the app is handling resizing/etc itself!

There's a Windows app I used to use that supports the same kind of thing for Windows (different key I think), no idea if there's one for Mac I'm afraid - or whether it can be configured to work that way, but there probably is one so it would be worth investigating if this sounds useful to you I'd say!