SQL Developer - Oracle SQL Developer is a free, development environment that simplifies the management of Oracle Database in both traditional and Cloud deployments.
DBeaver - DBeaver - Universal Database Manager and SQL Client.
DataGrip - Tool for SQL and databases
SQuirreL SQL - SQuirreL SQL is an open-source Java SQL Client program for any JDBC compliant database
SQLTools++ - Home of SQLTools++
dbForge Studio for Oracle - dbForge Studio for Oracle is a powerful IDE used by Oracle SQL developers to development, administration, management, and synchronization of Oracle databases via a handy GUI.