Stylus is exactly it, thanks!
If I recall correctly, Stylish was pegging a CPU in Chrome whenever I was editing a style, which was my motivation for seeking out an alternative.
For those not familiar, Stylus (and Stylish before it) offers a really easy way to override the CSS of sites of your choosing, in ways of your choosing. As an example, for Hacker News, I do all kinds of things: increase the line spacing, constrain the width of the text, make it so that if I've visited a user's profile page then it displays as visited, etc. etc.
While I write my own style overrides, there is a mechanism to download overrides written by others. I've never tried it.
Wikipedia - https://en.wikipedia.org/wiki/Stylus_(browser_extension) - has some more info. From the intro:
"Stylus is a user style manager forked from Stylish for Chrome in 2017 after Stylish was bought by the analytics company SimilarWeb. The objective was to 'remove any and all analytics, and return to a more user-friendly UI.' It restored the user interface of Stylish 1.5.2 and removed Google Analytics."
