Userify - Userify is a cloud-based SSH key management solution.
MobaXterm - Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more
Ganymed SSH-2 - Ganymed SSH-2 for Java is a library which implements the SSH-2 protocol in pure Java.
KiTTY - KiTTY is a fork from version 0.70 of PuTTY. It adds extra features to PuTTY.
FireSSH - After 13 years and 25 million downloads later, Firefox has officially removed FireFTP and FireSSH support from the browser. Thus, I've ended support / development of the addons. I recommend switching to Waterfox to continue using the addons.
ConEmu - ConEmu-Maximus5 is a full-featured local terminal for Windows devs, admins and users. Get better console window with tabs, splits, Quake style, copy+paste, DosBox and PuTTY integration, and much more.