As part of the premium subscription, you can access all the training material e.g. Hadoop Professional training, Apache Spark professional training, Scala , Python, Java and much more being added regularly. As well as you can get access to many technology exclusive interview preparation material in the form of E-Book as well as Video cum Audio Book. See sample below, which you can use while travelling, driving car and put on the speaker, you can watch and listen on your smart TV, smart mobile phones etc. 
Even you can access EBook using the mobile phone, tablet, Desktop, MacBook, iPhone etc. During active subscription we are keep adding new material in every few days. And you can get access to that newly added material as well without even paying any additional fee. 
Regarding certification preparation material new questions, videos , study notes, revision notes are added those also you can get the access with this subscription. 
Based on candidates interviews feedback, we update our interview preparation material as well. And you can check this link, how frequently material is being updated. 
As on when new technology is introduced, we are also adding learning material regarding the same as well. Like we started this package with the only BigData technologies and now we have Cloud Computing material like AWS, Azure etc. Soon we would be adding material for the Data science, Machine Learning etc. Programming languages like Scala, Python , exclusive technology learning material like Apache NiFi etc are added.
We are also continuously publishes the books, which you can get access as part of this subscription. So go to this link and the all available material as part of annual subscription. 
CRT020 Spark Scala Certification CRT020 : PySpark Databricks Certification Hortonworks HDPSCD2019 Spark Scala Certification Exam Spark Professional Training Spark SQL Hands Training  PySpark : HandsOn Professional Training PySpark Structured Streaming Read Spark SQL Fundamental and Cookbook Spark Interview Questions Cloudera CCA175 Hadoop and Spark Developer Certifications