For a native Obsidian solution, you can use embedded queries. These are basically regular searches done inside the note using a codeblock. See the relevant docs here:
Alternatively, you can try plugin options like Dataview and Feeds, which I think might fit your needs.
The latter builds upon Dataview to create topical feeds based on backlinks to a feed / topic note. Like this:
If you want to do it using tags and Dataview, here’s a Dataview query you can adapt:
```dataview
TABLE without ID file.link as Source,
L.text AS "Quotes"
FROM "03 - Source notes/Readwise"
FLATTEN file.lists AS L
WHERE contains(L.tags, "#YOUR-TAG")
```
You have to change the path and the tag to fit your situation.
Here’s an example from my usage of the above:
The caveat here is that this only works if the quotes are in bullet list form.