Portfoleon is described as 'Make and share outstanding roadmaps * Quickly prepare for executive roadmap presentations * Involve stakeholders for better alignment and impact'. There are six alternatives to Portfoleon, not only websites but also apps for SaaS and Google Chrome. The best alternative is Productboard. It's not free, so if you're looking for a free alternative, you could try Jibility. Other great sites and apps similar to Portfoleon are Aha! (Paid), Roadmunk (Paid), ProductPlan (Paid) and ProdPad (Paid).
Productboard is a customer-driven product management system that empowers teams to get the right products to market, faster. It's a complete solution for understanding user needs, prioritizing what to build next, and aligning everyone on the roadmap.
Jibility is a free software tool for building roadmaps specifically designed for solving strategic challenges. A strategic roadmap is the bridge between strategy and execution; it helps you to focus on the right things and gain consensus among your team and stakeholders.