This should be closed, Brave is a Chromium based browser, and all Chrome extensions work with Brave.

If you are talking about bookmark syncing, Brave has recently frozen bookmark syncing because of security/functionality issues they are trying to figure out.

You can see details about this, noted at the top of their documentation page: https://support.brave.com/hc/en-us/articles/360021218111-How-do-I-set-up-Sync-

What exact support you mean? Because it Chromium-based you can install our existing Chrome extension