Nifty - Manage projects, work, and communications in one place.
productboard - Beautiful and powerful product management.
ZenHub - ZenHub is how the world's best software teams work together. Trusted by NASA, Docker, and Rackspace. Start free today!
Aha - Aha! is the new way to create visual product roadmaps. Web-based product management tools and roadmapping software for agile product managers.
Intercom on Product Management - The ultimate resource for aspiring product managers
ProdPad - ProdPad helps your team gather ideas, surface the best ones and turn them into product specs, and then put it all on a product roadmap.