Portfolio Prioritization by 500talents - Jira plugin to accelerate your product portfolio
Roadmap - Collision avoidance for projects and people
Nifty - Manage projects, work, and communications in one place.
productboard - Beautiful and powerful product management.
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.
ProductPlan - Cloud-based product roadmap software solution