Suddenly in 2021 there appeared an open source desktop email program that I can recommend as a great choice for general users.

MailSpring

Organic Maps is a great open source app for casual every-day navigation. It has an easy-to-read map display, navigation directions with voice, search for places, save favourite places and add new places, and not a lot else. The usability is decent and it looks good.

It's become my default mapping app, and it makes me ever so happy to have such a good open-source solution.