The latest Oracle PSUs for April 2019 for all DB versions and platforms have been released.
You may find more information at Master Note for Database Proactive Patch Program (Doc ID 756671.1) on My Oracle Support.
Regarding Oracle Database 19c please keep in mind that:
As of the Release date (16-Apr-2019) the only Oracle Database 19 software that is available is 19.2.0 for on-premise Exadata. Therefore, the following patches for Oracle Database 19 are only for on-premise Exadata systems that are running Oracle Database 19.2.0.Master Note for Database Proactive Patch Program (Doc ID 756671.1)
We hope that we will find the first PSUs for 19c on Linux platforms on July.