Large Oracle Migration Feature similar to restore from (Snowballed In) S3 that RDS SQL Server Has

Specific to Snowball, there's nothing inherent in the device or client that supports integration with ORCL (or any other flavor of a RDBMS) for import/export operations. Depending on the migration approach desired (reference: Oracle Database on AWS), Snowball can be leveraged to accelerate ingest of RMAN backups or dump files generated by Oracle Data Pump into s3, however those features are independent of Snowball itself. Similarly, re-hydrating any ORCL data that's been migrated via Snowball in RDS or EC2 would rely on operations external to the Snowball service (e.g. Database Migration Service).