MacTelnet 3 —
A telnet client with basic FTP features. Version 3.0 primarily written by Kevin Grant.
Free Download for Mac OS 9.x / 8.x
— 3.0b1, for Mac OS 9.x / 8.x, 2.6 MB, not actively developed
Free Download for System 7.x / 6.x
— 2.6, for System 7.x / 6.x, 1.0 MB, no longer supported
Also available as a full terminal for modern macOS.