Indeed, there are various ones cropping up on aliexpress for instance
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
However none on Banggood, which I consider a slightly up-market version of Ali. The quality looks a bit dubious. I'd expect a more substantial grommet arrangement on the cable. Obviously with something on a belt-clip the grommet has to be top notch, even better than for a corded power tool IMHO. Once 3rd party kit is looking a bit more like this:
Dogu. - Online shop of Japanese tools with Full English support
dogutool.com
Then perhaps I'll bite.