Since 2018, in no particular order, seasons from Doctor Who's original 26-year run have been released on Blu-ray as part of Doctor Who: The Collection. 16 seasons have already been released, each containing a significant amount of special features.
At the moment, most of the '60s era has yet to be given the Blu-ray treatment. This isn't too surprising, considering the number of episodes that are still missing. In recent years at least, many of these gaps have been completed with animation, so hopefully, we'll see another box set or two joining Season Two.
However, it's still looking likely that the remaining color seasons will be focused on more. At the moment, four seasons have yet to be released from the '70s, and only two from the '80s. So in terms of Doctor Who in color, there aren't too many gaps to complete in The Collection.
The '90s
However, there is one more possible box set that could be released. Specifically, a release covering the '90s and early '00s - best known to Classic Series fans as "the Wilderness Years". Could a box set be released covering this period?
On the surface, it doesn't look like there's much that could be included. After all, the only official Doctor Who story released during this time was the TV movie starring Paul McGann in 1996. This story has already been released on Blu-ray, at least in the UK.
But looking further, there is a great deal of material that was released during this long gap. While I doubt that Children in Need special Dimensions in Time will ever be released, it's very easy to imagine that the documentary More Than 30 Years in the TARDIS would be included in a box set. There's also the Red Nose Day parody The Curse of Fatal Death, which is always a joy to see, especially as Steven Moffat's first Doctor Who story on television.
The '00s
Going beyond the '90s, there was a surprising amount of broadcast content for Doctor Who in the years before the New Series, usually in the form of partially animated webcasts. First, there was Death Comes to Time from 2001, starring Sylvester McCoy. This intriguing story presented itself as an alternative end for the Seventh Doctor—and even the Classic Series itself. Canon or not, it was exciting to be "watching" Doctor Who every week.
The following year gave us Real Time, a collaboration between the BBC and Big Finish. This story featured the Sixth Doctor and his companion Evelyn Smythe against the Cybermen. Real Time was shockingly violent and disturbing, and highlighted that Doctor Who at this point was mainly for adults. While a CD of the audio-only version is available, the animated webcast hasn't been available for years, so it would be great to see it as part of a new collection.
The third webcast released was Big Finish's take on Shada. Before the Fourth Doctor story was completed via animation in 2017, Big Finish adapted their own version, starring Paul McGann as the Eighth Doctor.
Interestingly, while this version of the story was included in previous DVD releases of Shada, it wasn't included in the Season 17 box set. Perhaps because the set included quite a few versions of the story already - the incomplete version released on VHS in 1992; the animated omnibus from 2017, and of course, the box set's new six-part version. Or perhaps they're saving the webcast for another release altogether?
Celebrating the Wilderness Years
The last webcast was something much more ambitious: a new, fully animated revival, starring Richard E. Grant as the Ninth Doctor! Of course, the announcement of a new live-action revival of Doctor Who in Sep 2003 definitely overshadowed Scream of the Shalka when it was released just a couple of months later. At the very least, it's a fascinating glimpse into what could have been if the New Series hadn't happened.
Altogether, there's a lot of content that could be brought together for a potential Wilderness Years box set. Perhaps even better though is the chance for a new documentary or two. There's a great deal that's worth exploring during the 16-year gap - both why Doctor Who was off air for so long, and how it was eventually brought back. Considering the high quality of the special features made for The Collection so far, I believe a documentary like that would be worth the price of the box set alone.
But on top of all of that, a Wilderness Years box set would be great because it would be the best way of celebrating that time. Not the fact that Doctor Who was off the air for so long. But the fact that it still endured. Thanks to an incredibly dedicated fandom, Doctor Who stories continued to be told in books, comics, audios, and of course, webcasts.
That level of enduring dedication to a series that had already lasted for 26 years ensured that the show was never forgotten. More importantly, it also ensured that the show did eventually return, in a revival that wasn't just loved by fans, but also created a new fandom of its own.