GoVisually - GoVisually empowers creative teams to deliver better designs, by providing a simple way to review and approve designs quickly and easily
Xmind - Xmind is a brainstorming and mind mapping application.
Ziflow - Online Proofing software from Ziflow keeps teams connected and collaborating by providing a single source of truth for creative review and approval.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
PageProof - Online proofing of anything and everything, made simple. Streamline feedback for easy collaboration, secure workflows, and faster approvals. PageProof. The smarter way to review.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.