Microsoft Office Access - Access is now much more than a way to create desktop databases. It’s an easy-to-use tool for quickly creating browser-based database applications.
Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.
My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.
Freeplane - Freeplane is a powerful and free software for building mind maps.
MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.