I've been looking for the same for quite a while, especially TNg.
I own all of ds9, tng and voyager on dvd, but none with descriptions, I regularly check a certain well known website whose name is associated with underground places, but as Hailey said, no luck.

I'd love to share the series with my lady, but can't due to lack of description, so if there is anywhere to get the episodes with description, please send me a pm as well.

I'm curious, what are the current legalities of Audio Description tracks? I mean, obviously there's the copyright issue with distributing episodes with integrated audio tracks, but what of a service of creating a standalone description track?

On that note, there's also a few lists of audio description services [here] and [here], though not sure if they'd touch commercial TV/film programming.

@4 regarding rights, not sure about the idea of creating a service which would create a separate track and then keep it in sync, though I think that would be relatively safe especially if you'd need to supply the original movie/TV show yourself. For commercial description tracks, this is where you run into problems and why so much of the trek description is now lost.

A description track can be ordered by a completely different company than the original studio which made the show. This especially happened with UK TV channels like Sky ordering description for US shows because British law requires much more content to be described. But because the description wasn't made by the original studio it very often isn't included when a show goes to streaming or gets a DVD release. A perfect recent example is game of thrones, which for the longest time could only be legally watched with AD on UK TV, while everywhere else it was available without description because HBO didn't care about accessibility or audio description. This only changed after they got sued by I think the American Council of the blind and lost.

Which brings us back to Star Trek which is a similar story. The little recorded 90's trek we have floating around also appears to be description made for I think Sky in the UK. Then either whoever was recording didn't do it consistently, or Sky didn't describe every episode which is why we just have a handful of random episodes preserved. The original series descriptions were also made for UK TV, this time the sci-fi channel and it's a similar story there. THis funnily enough also happened as recently as with Star Trek Discovery, which at first launched exclusively on CBS Access in the US, and as a Netflix original everywhere else. Netflix at this point really payed attention to describing anything that was an original, so for Discovery's 1st season it had AD on Netflix and absolutely nothing on CBS which caused a bit of outcry. THis eventually changed and now the renamed Paramount Plus has all the new trek series described, which is good because they took them off Netflix.

So the best we can probably do is try contacting Paramount to ask for this. I'm not sure if they can recover the old Sky tracks for these shows (I vaguely recall the 2 companies are merged in some way now). However I'm not sure how possible this is, in which case they'd have to make completely new tracks from scratch. Considering we're looking at hundreds of episodes and days of audio for what's now over 30 year old material I guess they don't think it financially worthwhile, beloved as it may be.

@5, I was talking about a different site which does not contain such a feature. They do appear to host random clips from Voyager / TNG / DS9, but it's way too random and also difficult to find amongst all the clutter anyway. The site you were thinking of unfortunately just host the original TV series along with much more modern TV releases.
I doubt be my eyes would do this, but Ira might. Unfortunately that's way outside my budget at the moment. Also getting the screen to show properly would get... pretty tiring. Plus I tend to binge watch, which they probably wouldn't be happy about.
I've been working my way through voyager and it's fairly easy to follow, there are just those weird moments such as action sequences, not to mention long periods of silence where it's obvious something is going on on screen. The fact that they're almost always relaying orders and telling each other what they're doing helps a great deal, though. I'm totally blind as well.