1) Ask Me WordPress Theme: Ask Me theme is a responsive and retina ready WordPress Questions and Answers theme which comes with 6 types of homepage layouts.

2) Q-and-A WordPress Theme: Q-and-A theme is a responsive WordPress questions and answers theme which supports Google fonts.

Question Answer Wordpress Plugins

• AnsPress. AnsPress is a completely free WordPress Q&A plugin. ...
• WP-Answers. ...
• Heroic WordPress FAQ. ...
• DW Question & Answer. ...
• Sabai Discuss. ...
• YITH WooCommerce Questions & Answers. ...
• bbPress

What is the free WordPress plugin for question answer?AnsPress

AnsPress is a profound and easy to use WordPress plugin that allows you to add question and answer section just like quora.com and stackoverflow.com. Equipped with a range of customization options, the plugin allows you to change the look and feel of your forum.see also from codecanyon