This is probably one of the most useful extensions I've come across. For online shopping and board forums, just open whatever products/topics you like and it will automatically close duplicated tabs instantly, saving so much time and headaches. You have to set them up a bit. If you don't know how to write regex, ask an AI. For example, with Amazon you can use ^(.*?(?:dp|gp\/product)\/) to compare only the ASIN in the URL.
A few quirks: some params it doesn't recognize; if you mass-open bookmarks from the same domain, because the tabs aren't loaded completely, it will mistakenly close them all but one if "auto close dupes" is on.
I also recommend the extension "ClearURLs". It removes almost all trailing trackers in an URL keeping it very clean.

This is my first extension review, but I want to express that this is the first tab de-duplicator extension I've encountered that performs this straightforward task in a streamlined and intelligent manner. Thanks!