Wine Reviews released Putty for Mac 8.7.0 for MacOS today. Putty 8.7.0 now has full support for macOS High Sierra.
https://winonmacs.com/2017/11/10/putty-for-mac-8-7-0-has-been-released-with-macos-high-sierra-support/
https://winonmacs.com/2017/11/10/putty-for-mac-8-7-0-has-been-released-with-macos-high-sierra-support/