Xshell by NetSarang Computer, Inc. is a famous pack of secure terminal emulators with SSH, TELNET, RLOGIN, SFTP and Serial support. Sadly, Xshell for Mac has not been officially released yet. Nevertheless, you can choose one of the apps listed here and use it instead. All the apps offer the same kind of terminal emulating functions as Xshell for Mac.
Feel free to add any alternative to Xshell for Mac that you know of.
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They say they are going to release the Mac version of XShell pretty soon. See the official forums https://www.netsarang.com/forum/xshell/1350/Xshell_for_OS_X The entry dates back to October 2015, so I guess, we'll see it sometime next...