I normally solve this problem by buying another arduino Have you thought about making some with buttons and pull-up resistors on? Or maybe with voltage divider for the buttons?Just to have some options to make it easier for some projects.
bld,I could. Will you describe what you would do with these buttons? It makes me understand more about where to put them and how many to add.FYI, if you connect buttons to arduino pins, you can enable internal pull-up resistors so you don't need external resistors.