Haven't bought anything lately but thinking about buying a subwoofer for my study.
Oooh! What are you looking at in consideration?
I can't really help with suggesting ready-made options much, since I have always built my own and those for many "friends" over the years. All my parts come from this side of the globe, mostly.
I did buy four really nice Jamo fifteen inch efforts back in the '90s, but Jamo is now a part of Klipsch, so not sure about the newer products. Pretty sure they still have an assembly plant in Denmark.
I have also bought Visaton from Germany before, imported to here from Canada. They don't make very large ones anymore, though.
If it's for a small room, modern tech will allow a much smaller driver size with decent output, than in years past, especially if you look for a servo controlled variety. I know Yamaha offers a superior servo type, available the world over, but I have not heard one outside of a showroom.
I can tell you that most of the time, two smaller subwoofers will sound better than one big one, especially if you can separate them into areas of your room to help with modal inconsistencies inherent to every listening space.
Have you calculated your cubic space, yet? Do you know how much subwoofer you need?
I said I couldn't help, and I can't, but maybe I can offer more things to think about, which probably won't help.
OOps, forget the Yamaha. I just went looking for the ones I had seen and they are no longer available. Plenty of Pro sound stuff, but not what you need for a home study.