Gravity Forms takes the cake when it comes to WordPress contact form plugins. It's a paid plug-in with features such as in line html content, import/export forms, conditional form fields, email notification routing, enhanced custom fields, validation for multiple forms, form scheduling, limit form entries, post image field, post category field, integrate with other forms using hooks, visual form editor and many more features.
Official site can be found here.
Gravity Forms is the only form plugin I use and recommend others use. It's super easy to use and advanced. You can build complex forms easily by dragging and dropping form functions ajax-style, so it literally takes a minute to build a form.
Features I really like:
Schedule Forms – Only want a form available for a limited period of time? Set a start and end date to limit form access and display a custom message when the form has expired.
Pricing Fields – Gravity Forms makes it's easy to create order forms. Order forms can incorporate pricing specific fields to allow your users to make selections and generate a total based on product and option selections.
Form Builder – Quickly build and design your WordPress forms using the form editor. Select your fields, configure your options, and easily embed forms on your WordPress powered site using the built in tools.
Another reason I use Gravity Forms is because it saves every form submission inside your wp database so you can easily access and answer every query.
14 Free WordPress Contact Form Plugins
Contact Form 7
Manages multiple contact forms. Form and mail has a flexible layout for easy customization with simple markup. Supports Ajax-powered submitting, CAPTCHA, Akismet spam filtering and more.
Official site can be found here. Also comes as a widget that can be downloaded here.
Fast Secure Contact Form
This plug-in will let visitors email the site's admin. Features an easy-to-use admin panel, multi-form feature, auto-responder and an option to redirect visitors to any URL. Supports CAPTCHA and Akismet for spam prevention. Any type of extra fields can be added to your liking. Official site here.
Clean-Contact
Simple contact form option. Advanced spam bot protection, out-of-the-box install, short code support, no external Javascript libraries required, supports custom styling using CSS, multi-language.
ONW Simple Contact Form
Simple form that can be added to any page or post through the editor or short code. Non-customizable form, though appearance can be altered using CSS. reCAPTCHA integration possible. Also supports use with multiple sites.
Scaleable Contact Form
Highly customizable. Uses CAPTCHA. Required and non-required fields can be configured. 5 different field types, all labels and buttons can be modified, optional confirmation-mail to user. Can be used as a regular send form or Ajax driven.
SimpleModal Contact Form (SMCF)
Ajax-powered modal contact form. Utilizes the jQuery library and the SimpleModal jQuery plug-in. Has options to include certain form elements such as subject field and sending a copy to the user.
FormBuilder
This plug-in allows you to build complex forms in the admin interface without needing to know PHP or HTML. Features premade forms for quick setup, forms can be placed anywhere, multiple forms on one page, split forms into multiple pages, personalized auto-responses, built-in anti spam and much more.
Official site here.
ContactBuddy
Add a simple contact form to widgets, posts and pages. Contains the following fields: name, email, subject, message. A reCAPTCHA validator can be added. Submissions sent to any email specified by the administrator of the site.
Contact WP
This plug-in is very easy to use, and lets you create a simple feedback submission form that is secure, quick and easy for any user to use. Multiple text fields are generated, which can be edited from the admin panel. Extra fields are easy to add.
MM Forms Pro
Comes as both free and Pro version. Some features include: set number of submissions, limit who can see it, make time-limited forms, redirect after submissions, multiple forms, CAPTCHA, send HTML formatted emails and much more.
Grunion Contact Form
Add a contact form to any widget, post or page. Choose which emails forms are being sent to.
TDO Mini Forms
Add highly customizable forms that allow non-registered and/or registered users to submit and edit posts and pages. It's easy to keep any new posts as drafts and edits as revisions until approved by admin (customizable). Many settings and options available.
Formidable Forms
It's quick and easy to build forms with the drag and drop interface and in-place editing. Make your own custom forms or use one of the templates. You can also use short codes and spam catching services if wanted.
Contact Form (by contactme.com)
Contact form and button. Part of an online suite with many more tools. Features include: custom fields (text, dropdown menus, radio buttons, checkboxes and more), editable through your admin panel, include your logo/contact info or social links on the form, many languages supported and more.