Freeplane - Freeplane is a powerful and free software for building mind maps.
Ideanote - Ideanote is the #1 rated Idea Management solution for companies of all sizes. Collect, develop and manage more of the right ideas from customers and employees to drive your growth.
Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.
Monkkee - Keep a private journal securely on the Internet – to provide a convenient user experience your...
OmniOutliner - OmniOutliner is a writing app for collecting information, outlining ideas, adding structure to any sort of writing.
Idea Notebook - Idea Notebook is an app that allows you to keep track of your logs business ideas and track as well as organize them.