there’s been many a time i’ve been out in the middle of nowhere with a friend or family member and google maps stops working on their phone, and i get to pull out OM and save the day :^)

i currently use tuta. it has a free tier, offers encryption, is open source, gdpr-compliant, and is 100% powered by green energy.

i have used mailbox in the past, which is paid (cheapest tier is ~€12/yr). i can recommend it as well.