The year 1980 saw a major change in the production of Doctor Who, as John Nathan-Turner took over as producer. Although this was the top job on the show, it's probably fair to say that the actual nature of the stories was more affected by his script editors than by he himself - the modern "showrunner" job description being shared between the two roles in those days. Nonetheless, 1980 was a break-point in the show's history that was more than simply a change in decade, and since the next truly major change came in December 1989, with the cancellation, "'80s Doctor Who" is very clearly a distinct thing.
So, having reached the last companion of the classic era, now it's time to look back over that decade, as I did with the '60s and '70s, and look at some characters from the show that weren't companions, but could be in our own RPGs. One of the rules I'm using here is that the character in question should have survived whatever story they appeared in, so that it's possible for some PC group to turn up and collect them afterwards. This, unfortunately, rules out the only decent candidate I could find from the Sixth Doctor's era, namely Orcini from Revelation of the Daleks. Indeed, three of my four main examples are going to turn out to be from the Seventh Doctor's run. (Which, probably not coincidentally, lines up nicely with Andrew Cartmel's run as script editor, rather than Eric Saward's).