I have had my students doing a concept map final project for years. Many of them use bubbl.us. But I do like to see them add images to their map. So I recommend they download the .jpg image of it, import it into PowerPoint and add more to what bubbl has created (though they then can no longer modify it).
You did miss one that I find especially easy and intuitive to use: https://tobloef.com/text2mindmap/ You start with an outline of concepts and it will turn it into a visual concept map. Then you can play around with it, move things around and adjust the colors based on levels or branches.
I like draw.io for collaborative mapping. :)
I have had my students doing a concept map final project for years. Many of them use bubbl.us. But I do like to see them add images to their map. So I recommend they download the .jpg image of it, import it into PowerPoint and add more to what bubbl has created (though they then can no longer modify it).
You did miss one that I find especially easy and intuitive to use: https://tobloef.com/text2mindmap/ You start with an outline of concepts and it will turn it into a visual concept map. Then you can play around with it, move things around and adjust the colors based on levels or branches.
though there does seem to be a limit of 3 levels deep you can go with text2mindmap.