In the past there used to be something called UDDI registry to which we would publish the web service so that there is a catalog of the services that are available. Off late i believe you can use a combination of API Gateway\Portal to create a similar catalog. For future, i read in the documentation that we are going to have a new product called API Control plane that will work with API Gateway to provide similar functionality. I am not sure about the future roadmap of the API Portal but in current version that is the place where you can setup the web services catalog.
Having said that, IBM has yet to share an official roadmap for webMethods products so no one knows which products in the wM Suite will be available and which one will be dropped in future release. There is a lack of communication from the vendor on it. If you do not want to wait for IBM to release a roadmap or what plans they have for the product then I would recommend you build your own Service catalog based on the recommendations what Holger has provided above. Create a UI application and call the “https://:/ws” to get all the list of web services from the server and group them based on functionality for serving the catalog.
#Integration-Server-and-ESB#webMethods