Guahan Web

This plugin gives you the flexibility to add Ajax handling for your comments to keep the page from having to refresh every post. The administration panel will allow you to customize your processing, success and error messages.
Additionally, this plugin gives you the option of setting up the WYSIWYG editor for comment submission as well. The admin panel will give you the option to show/hide various button groups for the editor and only allows basic editing capabilities. If logged in as administrator, you will still receive the full WYSIWYG editor for your commenting.

GuahanWeb AJAX & WYSIWYG Comments

Adds customization for Ajax commenting and allows for enabling of custom WYSIWYG editor.

kubiq

This plugin will replace raw textarea by TinyMCE WYSIWYG editor when “Use HTML content type” is checked. 
Works for both Mail and Mail (2) in Contact Form 7.

Contact Form 7 – email body TinyMCE editor

TinyMCE WYSIWYG editor when "Use HTML content type" is checked in Contact Form 7 Mail and Mail (2)

GuahanWeb AJAX & WYSIWYG Comments vs Contact Form 7 – email body TinyMCE editor