Not to be outdone by Nina, Gustavo also has a pretty chill script for comparing character sets across two UFOs. It appears that Commercial Type has one as well. There are multiple people writing the same scripts. Does that seem wasteful to you? At any rate, here is Gustavo’s.
hTools is a beastly extension that allows you to do many things across a range of selected glyphs, or open fonts. On the overview, Gustavo says, “hTools2 is a collection of tools and objects for type-design & font-production work. It is written in Python and specially tailored for use with RoboFont.”