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.
HTTPie - CLI HTTP that will make you smile. JSON support, syntax highlighting, wget-like downloads, extensions, and more.
GNU Wget - GNU Wget is a free software package for retrieving files using HTTP(S) and FTP, the most...
Yummy FTP Pro - Pro-level, fast, reliable FTP/S + SFTP + WebDAV/S client.
SiteSucker - SiteSucker is a Macintosh application that automatically downloads Web sites from the Internet.