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.
Google Structured Data Testing Tool - Google Structured Data Testing Tool
Wincher - The Easiest to Use Keyword Rank Tracker for SEO. Track all your important keywords and get daily updates.
Index Buddy by GSoftwareLab - All of your backlinks will be quickly indexed! Index Buddy makes backlink and domain indexing simple and quick.
Ahrefs - Ahrefs is a toolset for SEO and marketing. We have tools for backlink research, organic traffic research, keyword research, content marketing & more. Give Ahrefs a try!
Schema.org - Schema.org provides schemas for structured data on the Internet, on web pages, in email messages, and beyond.