RAW is an open web app that creates visualisations that you can then export in SVG or PNG format. There are literally dozens of styles. Check out the video to see how it works.
LucidChart is an online flowchart maker. If you have an .edu email address you can sign up for a free account with more benefits, although it’s difficult to know what they are or if you have been granted education status. Regardless, the basic functions are worthwhile.
Coggle is an online collaborative mind-mapping tool that you can use to take notes, brainstorm or share information. You can drag and drop images, change colours, add comments to nodes and chat. The free version gives you only 1 private diagram but unlimited public diagrams, and you can download as PDF or various image formats.
Text to Mind Map – this is another very simple online tool that will convert a hierarchical list into a mind map in seconds.