Survey Monkey - Create and publish online surveys in minutes, and view results graphically and in real time. SurveyMonkey provides free online questionnaire and survey software.
Jetpack - Jetpack offers SEO and security plugins for Wordpress.
Typeform - Create beautiful, next-generation online forms with Typeform, the form & survey builder that makes asking questions easy & human on any device. Try it FREE!
WP User Manager - The most customizable profiles, community builder and membership WordPress plugin
Wufoo - Wufoo's HTML form builder helps you create online web forms. Use our web form creator to power your contact forms, online surveys, and event registrations.
Project Panorama - Project Panorama is an elegant and reliable WordPress manager plugin that comes with exciting features and tools that will allow managing your multiple WordPress sites with ease.