There are two approaches to displaying a list of a user's resources in your own portal or application depending on your needs.
MyAthens RSS feeds
There are two authenticated RSS feeds available that list the resources of the logged in user. Whilst primarily intended for use by the MyAthens toolbar, the addresses are available to all:
The first is a list of all the user's resources, the second a list of the ones they have marked as favourites in MyAthens.
The feeds can only be viewed after the user has signed in to OpenAthens so you would need to allow for this in your portal or application design.
An API call can be made for any of your users' IDs to return a list of available services and key information about those services including title, link and description. If you can predict a user's permission set(s) without identifying the specific user, you could use a consistent user ID to obtain this information; if not you would need to identify the user before sending the API call.
For details see the API documentation.