Xmind - Xmind is a brainstorming and mind mapping application.
Invision - Prototyping and collaboration for design teams
FreeMind - FreeMind is a premier free mind-mapping software written in Java.
Zeplin - Collaboration app for UI designers & frontend developers
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.