Flinto - The prototyping tool designers have been waiting for.
Intercom on Product Management - The ultimate resource for aspiring product managers
Base UI Sketch Framework - Huge set of everything you need to design and prototype
Product School - The global leader in product management training
Glyphy - Copy & paste fancy fonts + cool symbols ☞✺✐™
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.