Hm. I wonder if you could write a browser extension to just kill gifs in their tracks and only show the first frame without hover or whatever. Maybe. Didn't find a solution after a cursory look (only malware called Gif Jam) but this certainly seems possible in principle...

Someone on StackOverflow found a thing that accomplished it; maybe this can be converted into a userscript. If this would be really valuable to you, and you aren't up for doing it yourself, let me know — I might make this just for fun. https://stackoverflow.com/questions/5818003/stop-a-gif-animation-onload-on-mouseover-start-the-activation

EDIT: I made one. Weirdly it works on all sites except beehaw, though, and it just breaks gifs on beehaw. Probably some content security policy on beehaw preventing the images from loading for the JS? https://gist.github.com/phoenixeliot/45f0c6a04fffd84998ac8bc526c901fe

But it does successfully replace gifs with broken images, so maybe still net positive for people for whom gifs are a health hazard?

Some parts that can be configured:

Which sites it applies to:

    
// @match        https://beehaw.org/*
// @match        https://*

  

How to select which elements are considered gifs:

    
  var gifElements = document.querySelectorAll(
    'img[src$="gif"], img[alt*=animated]'
  );