FileZilla - FileZilla is an FTP, or file transfer protocol, client. It lets individuals transfer single files or batches to a web server. For many years, FTP was the standard for website design. Read more about FileZilla.
HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.
aria2 for Android - Port of aria2 for Android with builtin front-end (aria2-webui).
WebCopy - Cyotek WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.
Forklift - The most advanced dual pane file manager and file transfer client for macOS.
SiteSucker - SiteSucker is a Macintosh application that automatically downloads Web sites from the Internet.