This document summarizes and compares 8 free and paid keyword research tools: Wordtracker, Ubersuggest, SEO Book, WordPot, Moz, Raven Tools, KeywordSpy, and SEMRush. It provides details on the features and functionality of each tool, including the number of keywords that can be tracked, pricing, data sources, and analysis available. The free tools generally allow searching of single keywords and have limitations on result volumes, while the paid tools provide more robust competitive analyses and tracking of hundreds of keywords.