I wish it had been ALL video, audible or not.
For animated images I'm not sure if it is exposed in the UI but in about:config change image.animation_mode to "once". If you want to replay it after that, you will need to open the image in a new tab. It is somewhat easy to miss them with this setting since even images at the bottom of the page will start their single animation when you hit pagedown (even if you move the page view up again almost immediately).
Mostly this autoplay blocking has been wonderful, a massive improvement. The one slight annoyance I've noticed is that the exceptions managament isn't as flexible as uBlock origin's configuration and you can't tell Firefox to unblock all of Bandcamp. I'm not sure if this is something that could potentially be done in an addon. The other thing I'd really like is a way to default "loop" to off on media controls so that I can just play the media once by default when I do play it. Oh yeah, for some reason I can't imagine Twitter tries hard to make videos repeat and current autoplay restrictions aren't able to stop that (I don't have an account so I suspect this is a "fuck you for not making an account" thing. I can't imagine anyone putting up with that more than briefly).