Website Downloader - Download source code from any website
Domainer - Manage All Your Domains and Websites
Web ScrapBook - A browser extension that captures the web page faithfully with highly customizable configurations.
Domain-Monitor.io - Looking for the complete domain and website uptime monitoring solution? Domain Monitor keeps an eye on your website, cron, SSL and domain name 24/7 and will alert you through Email, SMS and web when something stops working.
Offline Pages Pro - Offline Pages Pro is probably the world’s most advanced offline browser.
HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.