Why don't you support oracle database?
It's pretty obvious that open source developers won't bother with Oracle and it's licences. 
What's the justification for writing and orm in your free time for a database you don't use?

If you are interested, it's easy to add a backed for Oracle, and if you have a license you can actually even test the code.

Maybe you can convince your employer to pay for the effort as a path to migrate from Oracle to PostgreSQL. Oracle has a DB-API 2.0-compatible Python driver, I believe it's called `cx_Oracle`? If you want to add support for Oracle you should be able to subclass `Database` and implement the appropriate methods to get it working with Oracle.

As @oz123 alluded to, Oracle is a proprietary database. I have no interest in supporting or maintaining support for it. Thank you! I'll try it.
I often need to write tools about existing apps, which are based on Oracle, and I love peewee, and when I'm ready to use her, I find that she doesn't support Oracle. Why does peewee not support Oracle?