Community maintained list of resources for Marketplace vendors
View the Project on GitHub marketplace-vendor-resources/marketplace_docs
The Atlassian Developer Community (CDAC) is a great place to discuss your app building process and get help when you’re stuck. Additionally, Atlassian commonly makes announcements on there, such as new product releases, new APIs, deprecations, and more. Make sure you apply for access to the private Marketplace vendor topics in the developer community, to be able to see important non-public announcements and discussions.
There is also the Atlassian Developer Blog which Atlassian uses for announcements as well. However, important announcements are typically cross-posted to the Developer Community.
Once you have established your presence on the Marketplace and started selling your app, there are certain goals you can reach to become a Top Vendor. In the lowest tier Top Vendors get a special badge that identifies them as such on the Marketplace. In higher tiers there are more benefits, such as access to an Account Manager and advanced support. Check out the documentation on the requirements and benefits of the Top Vendor program for more details.