If there's an application you'd like to see in the App Store, or a capability the platform doesn't have yet - a customer-facing public API is one example that's come up in these docs as something VCloud doesn't currently offer - the best way to flag it is through Contact or the Help & Support page in the dashboard.
Specifics help: which application, or what you're trying to accomplish that the current dashboard doesn't let you do. A concrete use case is more useful to us than a general "it would be nice if."
Why some applications aren't in the catalog#
Not every application missing from the App Store is an oversight. Some open-source projects have license terms that aren't cleared yet for VCloud to offer as a managed service, so they're deliberately withheld rather than absent by accident. If you're asking about a specific app, mentioning it helps us prioritize clearing the ones people actually want.