This brand definitely doesn't count as small, but it definitely tries to count as sustainable- Patagonia! Here's a summary of their efforts and all around a great website to check out
Brands are one of the things I struggle with most, but Baggu for bags is good. The lunchbox and laptop case I got there were reasonably priced and have lasted 3 years now with no issues. Also, I would recommend "Good on You" as a site to look for sustainable brands/
i've heard lacemade is sustainable and gives off an old fashioned/cottagecore vibe. I honestly don't know much about it so maybe I'm wrong, but ppl can definitely look into it if interested.