Is there a way to copy several tables from an oracle database to another oracle database?

You should be looking into using dynamic schema:

https://knowledge.safe.com/articles/1157/dynamic-workflow-tutorial-destination-schema-as-a.html

Here's another description of the same concept from the training handbook:

https://safe-software.gitbooks.io/fme-desktop-advanced-training-2016/content/DesktopAdvanced4AdvancedR+W/4.09.CreatingDynamicTranslations.html

Yep that the way to go, no hassle and straight up input becomes output.

This is one of our ETL jobs in FME. It takes 50 minutes to run. Is there a better way to move data from one database to another (like sql script)? This is currently from oracle to oracle, but eventually am moving the output database to SQL server.

Worth noting is that the reprojector and attribute manager isn't needed.

If you need it to execute much faster, you should look into making a direct connection between the two Oracle instances (e.g. use Database Link) and use regular SQL statements to copy the table contents. You can of course use FME for this. This method is usually much, much faster than loading the data into FME before writing it back again.

From Oracle to SQL Server it gets a bit more tricky, but it seems doable, see e.g. https://www.sqlshack.com/link-sql-server-oracle-database/

You should also consider posting this as a separate question to get more visibility.