Salix
If you want free, I’d recommend Protom Mail.
For paid, I really like Mailbox.org and Posteo. They work with IMAP/POP3, CardDAV, and CalDAV
I like having congee or pho for breakfast
Sometimes I have fried rice with chinese sausage and eggs
Pan-fried Salmon, Miso Soup, and Rice is good too
I personally like both Posteo and mailbox.org, but they are paid email services.
You can use them for your email, contacts, calendars, and tasks. On Android, you can use Davx5 to sync them.
You make Vietnamese mung bean sweet soup
Magic Earth is not an open source app. They haven’t released any source code. Mentioning it as the OP title is about open source maps app.
https://www.magicearth.com/faq-en/
Will Magic Earth be Open Source?
No; since it is also used commercially (we have a paid Magic Earth SDK for business partners), we cannot make the code public.
That being said, I love using Magic Earth for driving. It works quite well as long as your area is up-to-date on OSM