Ah! A tricky one, while I do have resources for this, this is perhaps the least catered-to sector of piracy.
-Some blu-ray rips do have audio description tracks available. In most of the websites listed on the r/piracy subreddit, torrents come with extensive metadata info. At first it may seem like a block of text you're not interested in (it lists things like resolution, codec, fps, channels, etc.) but somewhere in the wall of text there's the info on audio and subtitles channels. Unfortunately a file having more than one English track doesn't guarantee AD, more often than not they're director/actors' commentary.
-However and luckily for everyone who is an english speaker on this earth, there's a website called audiovault.net with an extensive library of AD audio files in English for a bunch of media. I didn't go too deep into it, just downloaded Star Trek III to test it out. The audio was exactly what it said on the tin, but to state the obvious, just audio. Which is convenient if you don't care about the visuals, but for those of you who do, or intend to watch with non-visually impaired folks, this is an obvious inconvenience. So I decided to sync it with my copy of the movie on VLC, following this guide then going to tools → track synchronization to tweak the timing a bit.
Now, personally, I couldn't for the life of me sync star trek III and I stared at it in defeat for minutes until I realized that the blu-ray cut of this movie is fairly different from the one in Paramount+, as the latter starts with a brief recap of the previous movie (which I would have noticed if I paid attention to the very detailed description instead of mindlessly trying to sync it). Sure enough, I pulled the Paramount+ version and it was a perfect match. Probably ripped directly from Paramount+ in the first place. So I tried combinations of web rips (instead of blu ray rips) with the audiovault audio files, and sure enough, they either match perfectly or only need minor tweaks. This gave me immeasurable joy.
TL;DR: if you're looking to synchronize visuals with audio files from audiovault, download web rips instead of blue ray rips. You may slightly sacrifice visual quality, but save yourself much time.
That experience just confirmed the harsh reality to me: the easiest way to watch media with audio description continues to be streaming. However, when there's a will there's a way, and audiovault's library is pretty extensive, so it's at the very least worth looking into.
