Birdly - Birdly is an expense management and expense report solution for SMBs.
Product School - The global leader in product management training
PushMarket - Automate personalized emails for ecommerce (YC15)
The Product Manifesto - Product Managers face the biggest challenges of our day, which is why our community needs a common set of product principles.
Dynamic Campaigns by Sigstr - Share the most relevant content in every email
Intercom on Product Management - The ultimate resource for aspiring product managers