LinkChecker - LinkChecker is a free, GPL licensed website validator.
BetaList - BetaList provides an overview of upcoming internet startups. Discover and get early access to the future.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
Product Hunt - A website that lets users share and discover new products
Dead Link Checker - Check for broken links on any website
Betatesters.io - The platform connecting mobile developers and beta testers