I've just started using Disroot and they seem very good. They use only free
software and they say they do e-mail encryption (although I haven't tried
it), as well as free IMAP. They also host a Diaspora* pod, which is cool, as
well as cloud storage and some other cool services.
I had to disable LibreJS to sign up, or their captcha thing wouldn't work.
Also, their webmail doesn't load up for me when LibreJS is enabled, even
though it doesn't flag any of the code on their site as non-free. I've been
disabling LibreJS very briefly, to allow the webmail to load, then
re-enabling it, which seems to work fine.
Try it out! :-D