Chinar Aliyev has recently started to pick up on several of my blog posts regarding Parallel Execution and the corresponding new features introduced in Oracle 12c.
It is good to see that obviously Oracle has since then improved some of these and added new ones as well.
Here are some links to the corresponding posts:
New automatic Parallel Outer Join Null Handling in 18c
Improvements regarding automatic parallel distribution skew handling in 18c
Chinar has also put some more thoughts on the HASH JOIN BUFFERED operation: