Index Buddy by GSoftwareLab - All of your backlinks will be quickly indexed! Index Buddy makes backlink and domain indexing simple and quick.
KeywordTool.io - KeywordTool.io is the best FREE alternative to Google Keyword Planner and Ubersuggest. It uses Google's autocomplete feature to get over 750+ long-tail keywords for any given query.
Google Structured Data Testing Tool - Google Structured Data Testing Tool
Google Trends - Explore Google trending search topics with Google Trends.
Google SERP Snippet Optimization - SEOmofo tool replicates the appearance of a snippet in Google SERPs, which allows SEOs to optimize a page title and description for maximum click-through rate.
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition