While looking for some new features of 12.2 concerning the partitioning e.g the auto list functionality I found today the web site of Oracle Base

Partitioning Enhancements in Oracle Database 12c Release 2 (12.2)

having the subtopics of

• Automatic List Partitioning in Oracle Database 12c Release 2 (12.2)
• Create Table for Exchange With a Partitioned Table in Oracle Database 12c Release 2 (12.2)
• Multi-Column List Partitioning in Oracle Database 12c Release 2 (12.2)
• Online Conversion of a Non-Partitioned Table to a Partitioned Table in Oracle Database 12c Release 2 (12.2)
• Online SPLIT PARTITION and SPLIT SUBPARTITION in Oracle Database 12c Release 2 (12.2)
• Read-Only Partitions in Oracle Database 12c Release 2 (12.2)
• Partitioned External Tables in Oracle Database 12c Release 2 (12.2)
• Filtered Partition Maintenance Operations

and

Partitioning Enhancements in Oracle Database 12c Release 1 (12.1)

and

Cool New Features for Developers in 18c and 12c

having the subtopics like

• Real-Time Materialized Views (12.2)
• Row Limiting Clause (12.1)
• Case Insensitive Queries (12.2)
• Approximate Query Processing (12.1)
• Approximate Query Processing (12.2)

Some other interested things new with 12c Release 2 you will find blogs.oracle.com

Have fun

Rainer