This isn’t really a feature request, just an idea that popped into my head.
What if there was a polygon select tool (approximated to the nearest squares, which could be highlighted or something), and once you create a selection you could hit one of the other tool buttons/hotkeys to perform some action depending on which tool you chose.
So, for Fill it would fill the selection, for Edge it would outline the selection, for Fog of War it would show/hide the selection, etc.
Not a requirement by any means, but might be nifty if implemented well.