Time Table is a little project that I spun up in a couple of hours but turned out to be extremely helpful. I wrote the package to mimic the functionality of https://www.timeanddate.com/worldclock/meeting.html .
The basic idea is that this package displays lists of various time zones side-by-side with the time-zone’s normal working hours highlighted according to availability. You can add as many time zones as you like. This was very handy when working across with a multi-continent team and helped me see which times people would be available.