Hello @craftytrading ,
I am John from Report Pundit, a reporting and analytics app with more than 500 five-star reviews.
Report Pundit can list out the products which don't have any collections associated with the products.
And you can also filter the report based on tags, Product type, etc.
Our support team can create custom reports specific to your business. We have created custom reports for more than 10,000 Shopify merchants.
Contact us at firstname.lastname@example.org or our live chat support team for help.
Denis from the Advanced Reports here.
If you still looking for a solution, then I suggest trying our app.
You can apply filter by Collection Name with the "IS BLANK" condition to get only products without collections:
Please feel free to contact me via email@example.com if you have any additional questions.