Substack as a growing market

I'm a writer on substack (14,000 subscribers), and I've noticed a few of my fellow writers having brands sponsor one of their posts. I was wondering whether brands are starting to engage more with Substack as a platform, and if so, what are their metrics for choosing creators to work with? I would love to be able to leverage my platform to work with brands, but I know very little about the process. Thanks y'all!! <3