I'd say Star Wars is comparable, and even in the days of the old EU it didn't put out nearly as many novels as Star Trek ever has in a year.
The question was about the quantity of the source material, though, and Star Wars used to be way behind Trek in that regard, since it only had a handful of movies and a smattering of TV stuff that was retroactively decanonized. Now, though, SW is much more competitive in the size and scope of its source material, with multiple TV series joining the movies. (I realized a while back that there's probably a generation of kids now who think of Star Wars as an animated TV franchise with occasional live-action movies. Although now we're getting live-action TV series as well.)
Heh, perhaps the (in)famous Karen Traviss will find a new generation of Mandalorian fans who are growing up on The Mandalorian at present! It will be quite interesting to see the future state of the Star Wars fandom born in a post-Disney acquisition world. Oh hell, Kurtzman's team is overseeing a new generation of Star Trek fans courtesy of streaming television right now.
Which is as it should be. Iconic characters and concepts survive by reinventing themselves for new generations, not by stagnating in the past. Although that's why it worries me that modern continuations of franchises like ST and Doctor Who are so obsessed with nostalgia for the old stuff. TNG thrived by ignoring the TOS purists who complained about the changes and going out of its way to avoid ties to TOS as much as possible, instead building its own new mythology that expanded the franchise massively. Later shows in that era did occasionally connect to the past, but were mostly about building outward and forward rather than looking backward. But since Enterprise, new Trek has looked backward and revisited its past more and more. It's grown somewhat beyond that with Discovery season 3ff and hopefully with Prodigy, but it's still heavily dependent on what's come before.
Doctor Who? And if we're counting, say, the Marvel or DC Universes, you also have a wide breadth of source material: Batman novels, Superman novels, Wonder Woman novels, crossover novels, etc.
Spotted this from Amazon: https://www.amazon.com/Creating-Star-Trek-Next-Generation/dp/1801260524 It is called "Creating Star Trek The Next Generation: A Season by Season Companion - Season 1: 1987-1988", looks like there will be seven books in total, each covering one season of the show.
We have heard about Una McCormack’s Picard novel, Second Self, due at the beginning of May. I figure it’s good odds that we’ll see at least one Discovery novel, as well as the first SNW novel by the end of the year. I’d also wager that figuring out what’s going on there is part of why we haven’t heard much of what’s coming up next year just yet, since Discovery and Picard have been too serialized to just drop a “mission of the week” story into the time between episodes, so seeing where their next seasons are going will offer some room to maneuver. Throw in trying to figure out where to launch SNW, and that’s probably covering the summer 2021 plans. I mean, that’s all speculation on my part, but it’s not like the novels will just STOP. And since eight or nine per year has been the publication since the last contract negotiations happened, it’s easy to see them having that gap early and getting something near every month for summer/fall. I mean, that’s what happened THIS year. We had The Dark Veil in January and then nothing until May’s Wonderlands. This seems to be the normal for the time being.
I like to think there will always be an audience for standalone TOS novels, not to mention novels set during the latter-day series, including the newest ones: DISCO, PICARD, STRANGE NEW WORLDS, etc.
CrossCult has posted their cover for Second Self on their website: I don't think the English cover was revealed yet, but since CrossCult's previous Picard covers have all been identical to the US ones, it's safe to assume this one is too.
If Strange New Worlds doesn't anchor itself so hard to season-long plot arcs there might be a ton of opportunities for standalone SNW books. (I must admit my affection for Treklit has been almost entirely based on the ongoing arcs so I'm not personally super excited about that, but it does seem plausible.)