I don't know the exact list, but pricespy (prisjakt) is in a lot of countries. I have used .no/.se/.co.uk previously and they all seem to be at about the same level for their respective countries.
Sounds a lot like geizhals.de - price comparison site with detailed info on products, best for tech products though
Geizhals is amazing!
I started using it for price comparison almost 15 years ago, but nowadays I use it mainly as a database to filter for products which fit my needs and are available.
it's an awesome product search focused on depth not breadth. This site lets you filter headsets by connectors and dog food by taste.