Word Counter - A simple, beautiful word and character counter
Google Doc Publisher - Make Google Docs good-looking in two clicks
Word Count Tools - The must-have free word counter that provides an extensive report about the word count, character count, keyword density, readability & many other useful stats.
Content Editor 2.0 by Surfer - Content Editor is the most advanced content optimization tool that allows you to write and grade your work.
Count Wordsworth - Count Wordsworth makes it easy for you to monitor your literature-related metrics online.
SEO Minion - Chrome extension & Firefox add-on to help you with SEO