Web ScrapBook - A browser extension that captures the web page faithfully with highly customizable configurations.

HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.

Offline Pages Pro - Offline Pages Pro is probably the world’s most advanced offline browser.

GNU Wget - GNU Wget is a free software package for retrieving files using HTTP(S) and FTP, the most...

wpull - Wpull is a wget-compatible web downloader and crawler with WARC and Python/Lua scripting support

WebCopy - Cyotek WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.