Nomenclature on paint brushes has always been a bit sketchy.
The "camel hair" brush was not invented by a Mr. Camel, and it does not use hairs from camels. The bristles are squirrel hair.
Long ago you could buy "sable" brushes that actually used hairs from the sable, but the Soviet Government put a stop to that in the early 1970s. (Glad I was able to get mine while they were still available. No comparison to current production stuff.) No idea what they're made of now, but they still call them "sable brushes".
Any brush from China would be strictly a one-use deal, and only used on a "quick and dirty" job. I have a bird feeder and an old folding deck chair that got a coat of stain last night with a cheapo Chinese "chip brush" (as they are called.) Use 'em once and toss 'em.
Real paint brushes are made by companies like Purdy. Worth every penny.
You can still purchase brushes made with genuine Sable hair, from high end art material suppliers.
“kolinsky” Sable, is usually a higher quality preferred variant.
The brushes are usually very expensive though, and usually used for watercolor, and sometimes fine oil painting.
By “very expensive” I mean that a single small Sable brush will cost the same as a top of the line large pure bristle painters brush by a manufacturer like Corona.
As far as brush bristle materials go, there’s pig and boar bristle, which is separate into Noack and White( black is sometimes more expensive, but I don’t know if it’s actually any better)
Squirrel hair is sometimes used as a replacement for sable, as is Ox hair.
Goat hair, horse hair, etc. are also used for different types of brushes.
Badger hair is preferred for certain uses like thin washes of color, as well as fine shellac finishes over large areas, but genuine badge hair brushes are very expensive, and not easily available.
There are Badger hair brushes that are more readily available, but these are usually a mix of badger hair and boar bristle.
Nowadays there are plenty of brushes that are a mix of natural boarvor other hair, and synthetic, with the natural hair providing smooth covering, while the synthetic provides springiness which would be lost with pure natural bristle when using modern water based finishes.
Part of the issue with brushes, is they need to be chosen for the paint or finish being used, for not only things like oil or water based, but also for the viscosity of the finish, and where the finish is being applied.