WordCounter.net - Count words, sentences, paragraphs etc.
Heytools - JavaScript tools, AJAX tools and some fully server side tools.
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.
Word Calculator - Free online word calculator to count the number of words and characters in your text.
TextBuddy for macOS - A Swiss Army knife for plain text.
NimbleText - NimbleText is a text manipulation and code generation tool available online or as a free download.