Quuu Promote - Promote your content to influencers w/ curated content
Email Inspire - Discover the best of email design and marketing — Browse email newsletters from top brands.
PromoRepublic for Buffer - Daily content ideas for your Buffer posts
WhoSentWhat - We bring email newsletters from inbox to web
PRNEWS.IO - PRNEWS.IO provides guaranteed placement of sponsored content in online media around the world.
Really Good Emails - A large collection of good product email design.