This sample model is a good starting point for creating a subscription management system with a NoSQL database like MongoDB.
The idea is to store info about purchased software licenses, subscription payments, licensees assigned to users, and tracking history.

HTML report / online ER Diagram
Details
Target database: MongoDB
Diagram URL:
https://www.dbdiagrams.com/online-diagrams/subscription-tracking-nosql/
Moon Modeler project file:
https://www.dbdiagrams.com/online-diagrams/subscriptions-nosql.dmm