Really Good Emails - A large collection of good product email design.
Posteo - Web- and IMAP-based email service. 2GB cost 1€/month.
Email Inspire - Discover the best of email design and marketing — Browse email newsletters from top brands.
Inbox.lv - Inbox.lv Mail
Good Email Copy - Email copy from great companies.
CounterMail - Countermail is a web-based email service. It is hosted in Sweden. Its focus is on privacy.