Incidentally, Esc used to stop GIFs on a web page. Doesn't seem to do that (anymore?) in Chrome. (Oh, or Firefox, or Edge. IE is the only browser that still does that.)
There's an extension (SuperStop I believe?) that partly restores it if you shift-esc, but recently I've found that invasive keybindings in pages (Slack, I think?) can intercept this and stop it working.
I'd really like a whitelist somewhere of what keys/combos I'd like the page to be able to catch, vs those which I expect and rely on to perform native functions, and which shouldn't be hookable (Github trying to cleverly intercept '/' and take you to the search field would be great, if / wasn't already a shortcut for searching the page, etc.