I think currently some options are already moved to the menu to prevent an overflow. For example, the </> button is moved to the plus menu on my tablet. IIRC, that is based on the fact that a touch device is used. So the concept of
is already used. Therefore, it seems reasonable to expand this for more devices. Perhaps even based on the width rather than the type of device. My tablet has enough space in landscape mode for the button to format code. I guess there is also enough space for the list buttons. But I usually don’t use those. Code tags are more annoying to type, so I use that button frequently.
I also like nat’s suggestion of a setting where admins can choose the most important buttons for their community.