Chrome extension to modify websites

I have some hacks I use on some sites to take a few advantages of the website. (Don't really want to discuss each hack right now but maybe later)

These "hacks" are sometimes some additional CSS that I can add to the page using inspect element or some js that I put in the developer tools console and then navigate website (works best for SPA because otherwise, I have to execute it every time on navigation).

Would a chrome extension be beneficial for you which does the following?

You can specify rules (if URL matches) and if the current page matches with the rule add custom CSS or execute the specified script on the page.

Can you think of some use cases you might need this for?