Heytools - JavaScript tools, AJAX tools and some fully server side tools.
WordCounter.net - Count words, sentences, paragraphs etc.
TextBuddy for macOS - A Swiss Army knife for plain text.
KeywordDensityReport.com - Website Keyword Density Reports
NimbleText - NimbleText is a text manipulation and code generation tool available online or as a free download.
TextPipe - Search and Replace, Find and Replace, Web Sites, Database Extracts, XML, CSV, Tab, mainframe COBOL data and more