RobinGupta Bulk Domain Authority Checker - Free tool to bulk check domain authority, Page Authority, Spam score & IP Address.
LinkChecker - LinkChecker is a free, GPL licensed website validator.
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.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
Plerdy - Plerdy is a comprehensive conversation rate optimization software that caters to professional online marketers and agencies, allow them to enhance website performance and increase revenue greatly.
Checkbot - Checkbot will boost the SEO, speed and security of your site by checking you're following 50+ web best practices. Browser extension with free and paid plans.