You must not be looking very hard.
No, I'm not actively shopping at this time, but I do waste way too much time surfing bike stuff on the web when I should be working and I find rigid MTBs to be plentiful on craigslist but not on manufacturers' websites.
Kona, Trek, Salsa, Marin, etc. There are not many, but featherweight XC race bikes, bikepackers, and singlespeeds with rigid forks are common. They come and go with each model year.
Well, Trek seems to have four on their site today - but two are fatbikes and two are kids' bike with 20" and 24" wheels. So,
in my opinion that's zero "regular" rigid MTBs.
Kona has two rigid mountain bikes - the geared Unit X and SS Unit. The others are fatbikes or kids' bikes.
Looks like Salsa has two rigid fatbikes, and the Fargo. I guess the Fargo counts.
Marin doesn't appear to have any rigid MTBs, unless the Four Corners with drop bars counts - and it looks pretty cool. But, they don't list it under MTBs on their site.
Hey, I didn't come in to argue, believe me. Rigid (and steel) MTBs are the only bikes that interest me these days.
And I love drop bars. But I guess the reason I ride a 1993 (or '94, not sure) bike is because I haven't seen any rigid MTBs that I think would be any more fun or capable than what I already have.
I keep eyeing Surly bikes online but have never ridden one. I'm positively drooling over the Black Mountain Cycles Monstercross frame as well, but I guess my rather irrelevant point here is in the Rigid MTBs vs. Gravel Bikes debate, there aren't many new rigid MTBs to choose from.
Edited to add - that Orbea looks neat. I've heard that name, but it's not a brand I'm familiar with.