Retroflag, Binbok, and Nexigo are almost but not completely no-name companies and are making them. Retroflag and Binbok call theirs "gripcon" and Retroflag a "one-piece controller". Then there are tons of weird no-name companies calling them one-piece controllers:

https://www.amazon.com/s?k=nintendo+switch+controller+one-piece

Retroflag's the only one I've seen and it works fine for what it is. I prefer joycons in a grip to something like this:

https://www.amazon.com/RetroFlag-Switch-Controller-Accessory-Auto-turbo-Nintendo/dp/B0BMTQ5V6S