SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters
LinkChecker - LinkChecker is a free, GPL licensed website validator.
Linkody - Save time and money by managing your SEO linkbuilding with Linkody.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
SEOwl - Next-generation Rank Tracker & SEO Monitoring solution that understands modern SEO, finally
Dead Link Checker - Check for broken links on any website