LetterHunt - LetterHunt connects you to 10,000+ niche, active newsletter writers to promote your product.
Birdly - Birdly is an expense management and expense report solution for SMBs.
Newsletter Operating System - All-in-one dashboard to launch & grow your newsletter
PushMarket - Automate personalized emails for ecommerce (YC15)
Unzip.dev - Discover the latest developer trends
Dynamic Campaigns by Sigstr - Share the most relevant content in every email