Clive, I've been writing about serendipity and how to increase opportunities for it lately. I'm especially intrigued by several visual thinking tools that are using AI to enhance it.
ContextMinds uses it to suggest key words and concepts that may be related to your currently-selected topic. You can drag and drop ones that resonate with you into your concept map.
Ayoa automatically inserts topics into your mind map based on your criteria.
And Napkin, a visual note-taking tool, automatically surfaces older notes you've captured that are related to the one you're currently editing.
Here are links to several relevant articles I've written about these 3 serendipity-enhancing, AI-powered tools:
Ayoa and ContextMinds: 2 unique approaches to AI - https://mindmappingsoftwareblog.com/ayoa-contextminds-ai/
How Napkin inspires you to explore your ideas – visually - https://mindmappingsoftwareblog.com/napkin-interview/