Pulno - SEO Audit and Website Analysis. Pull up your SEO.
AWS – Cloud Practitioner Cert. - AWS – Cloud Practitioner Cert.
LinkChecker - LinkChecker is a free, GPL licensed website validator.
Azure AZ-103 - Azure AZ-103 is one of the best mobile apps introduced by Naveen Karamchetti that enables IT Professionals to manage Azure resources and subscriptions to configure cost quotas and subscription policies directly through their mobile phones.
BrokenLinkCheck - Free Broken Link Checker / Online Dead Link Checking Tool - find bad hyperlinks
Trailhead GO - Trailhead GO is an app introduced by salesforce.