There are various tools available for ETL testing, depending on the type, complexity, and scale of the ETL process. Data comparison tools, such as SQL Server Data Tools (SSDT), Informatica Data Validation Option (DVO), and Talend Data Quality, can be used to compare the data between the source and the destination, or between different destinations, to identify any discrepancies or mismatches. Additionally, data profiling tools like Data Quality Services (DQS), Trifacta Wrangler, and IBM InfoSphere DataStage can be used to analyze the data quality, structure, and content to identify any data issues. For measuring and optimizing the data performance, such as the data throughput, latency, and resource utilization, ETL Validator, Pentaho Data Integration, and Apache Airflow are useful tools. Lastly, Protegrity Data Security Platform, IBM InfoSphere Optim, and Oracle Data Masking and Subsetting are great for protecting data privacy and confidentiality.