I really don’t care for water brushes (though I use them occasionally) so I have amassed a decent stash of travel brushes and reviewed several here: https://www.scratchmadejournal.com/blog/reviews-of-travel-pocket-brushes-for-watercolor
(Be sure to read the post comments… I think there’s some good advice there!)
Since I wrote that review, I splurged and bought the Cheap Joe’s travel brush in the 100-percent sable. I love, love, love it! But I will also say that their Pseudo Sable works like a dream and is excellent quality for the price.