Referred to as "the poor man's meat", beans are a good source of protein and nutrients. Maybe for this reason, they appear in a couple of postive expressions, like:
andare a fagiolo a qualcuno
to suit somebody to a T
capitare a fagiolo
to happen at the right moment
Also, the fava bean in particular gets a special shout out in the following:
parlare della rava e della fava
(lit.) to speak of turnips and fava beans.
(fig.) to speak in detail
i fagioli
beans