Dendron - The note-taking tool that grows with you - makes it easy to add, find and share anything in seconds, regardless of how much information you have. Dead.
EDVO - transform a chaotic, overwhelming environment into your flexible learning playground.
Nototo - Looks like a spatial organization tools, similar to Muse.
Muse.app - Built by Mark McGranahan, Adam Wiggins, and team. Spun out of Ink & Switch, based on research into gestures they had been doing.
Kosmik - An infinite canvas for your notes, medias and web browsing.
Are.na - Save content, create collections, and connect ideas with other people. Visual bookmarking.
Kinopio - A space for thinking. Random cards on a browser screen.
Kanopi - Note-taking tool with notes, maps, and outliners.
Project Meta - visual playground for your notes - make sense of complicated research topics. "put paper notes on the table to help us think."
Infinity Maps - visual thinking and knowledge management combined
Notably.ai - Tool for UX research that does audio transcription then allows you to arrange snippets on a spatial canvas as sticky notes. Interesting summary of large swaths of notes when you zoom out.
Scrintal - infinite canvas with clickable cards that are notes.