Apache JMeter - Apache JMeter™.
Postman - The Collaboration Platform for API Development
Selenium - Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that.
TablePlus for Windows - A native GUI tool for MySQL, PostgreSQL, SQL Server & more
locust - An open source load testing tool written in Python.
Postman for Mac (Beta) - Build, test, and document your APIs faster