From reading around posteo.de seems like a good choice. I use their service
and am happy so far. They cost you one euro a month and offer a high level of
privacy. Two free aliases, more can be bought cheap. I don't remeber the
included space but it's ok and more can be bought at a low cost.
They promise that
All Posteo servers exclusively use open source software, for security
reasons. The hard drives are fully encrypted using LUKS – and all
connections between our servers are encrypted
Furthermore, fsf say:
Some of these services are gratis, but that's a separate issue. Recall that
"free software" refers to freedom, not price.
https://posteo.de: Fully compliant with LibreJS's standards, but a bug in
LibreJS causes the site to not work when the plugin is enabled. Does not work