1 - JoomTestimonials - by JoomBoost
The best out there for displaying testimonials and reviews, component that showcase testimonials and suggestions in your website, this component allow your users to submit their testimonials and feedbacks in a beautiful and creative way.
2 - MyTestimonials - by JoomUnited
Add clients feedback or get their testimonial from your website frontend/backend, then display your score and review in Google search results. My testimonials got integration with the Google Company Rich Snippet, review and testimonials.
3 - JUX Testimonial - by JoomlaUX
Awesome component which helps you to display all of your clients, partners’ testimonials on your website at different positions with many beautiful styles.
4 - SkyLine Testimonials - ExtStore
Easy way to collect customer feedbacks and amicably show them on the Joomla with this component
5 - Testimonial Fader - Infyways Solutions
Easy to use extension which comes with a component, a Ajax based form and a testimonial showcase module. It allows users to add testimonials in the front-end using the component or the ajax module.