Blazemeter - BlazeMeter is a self- service performance load testing cloud tool
WebLOAD - WebLOAD - The most flexible and cost effective software for enterprise load, stress and performance testing, integrated with DevOps processes. Click for details
flood.io - Load Testing for Everyone
StresStimulus - Load testing tool for websites and mobile that works with hard-to-test applications.
gatling - A high performance web server. Small! (125k static Linux-x86 binary with HTTP, FTP and SMB support).
OctoPerf - OctoPerf is a SaaS load testing solution, based on JMeter.