The first RU (Release Update) for Oracle 12.2 is available on most platforms since July 18, 2017. And of course I started applying the first RU for Oracle Database 12.2.0.1 as soon as it got released.
See: https://mikedietrichde.com/2017/07/19/first-ru-oracle-12-2-0-1-available/
Download the RU 12.2.0.1.170718 for Linux
First of all I downloaded the Database RU 12.2.0.1.170718 Patch 26123830 for Linux from MyOracle Support. To my absolute surprise it was very small compared to previous Proactive Bundle Patches such as the April 2017 one. It has just 40 MB in size (no typo!).

Download the first RU (Release Update) July 2017 for Oracle