Optimizely - A/B testing you'll actually use.
PreFlight - Preflight is an Automated Web Testing tool. Allows everyone to automate Web UI tests.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
AbTest.io - A free url shortener with A/B testing features
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.
Marpipe - Automate Your Ad Testing, Optimize Your Creative