Content

A couple of ways to look for emergent ideas are:

Basic Search

Ctrl + O Open command that includes referenced but not created notes
Ctrl + Shift + F Search and searching for a word, this will include all mentions even in the body of the note

A collection of dataview queries that show those notes that have the most outgoing, incoming, orphans, and embedded search for keyword.

Outgoing heavy linking notes are probably a good candidate for a Map of Content.
Incoming heavy linking notes are probably a good candidate for fleshing out the note more so that it can elevate to a Map of Content.
Embedded search for a keyword are tracking a specific relationship you think will likely have interesting outcomes, these will be specific to the topics you take notes on
Orphans are notes that are good candidates for deleting or otherwise evolving their relationship within your vault.

Using the graph view of excalibrain and the metadata set on your notes to see graphically the relationships between your notes.