My personal favorite e-mail provider mailbox.org is giving away Christmas vouchers until January 10, 2020, for each new customer registration. Details if you read on.
Mailbox.org is an e-mail and calendaring/office suite provider based in Germany. They are very privacy focused, run on renewable energy exclusively, and are committed to using Open Source wherever possible. They are promoters of open standards such as IMAP and SMTP, CalDav, CardDav and WebDav for their offerings. They use Open-Xchange as their software of choice. Their service offers e-mail, calendar, contacts, tasks, file storage, word processing, spreadsheet and presentation software as well as an integrated PGP module for secure encrypted e-mails.
This year, from now until January 10, 2020, each new customer can get a voucher of 6 Euros upon registration and using the voucher code “christmas2019”. All details and conditions in the linked blog post.
The Open-Xchange web front-end is very accessible in many parts, and more stuff is added frequently with each release. I use it for my personal e-mail, and am really liking it. You can also use any compatible IMAP/SMTP mail client, the open standards integrate extremely well with iOS and MacOS.
Disclaimer: I am not getting any money from this promotion. I pass this on because I like their service a lot and can only recommend it to others. And this seems like a pretty good incentive for trying it for a bit. Enjoy!