Userify - Userify is a cloud-based SSH key management solution.
PuTTY - Popular free terminal application. Mostly used as an SSH client.
Ganymed SSH-2 - Ganymed SSH-2 for Java is a library which implements the SSH-2 protocol in pure Java.
MobaXterm - Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more
SecureBridge - Сlient and server components for SSH, SFTP, FTPS, SSL, HTTP/HTTPS, WebSocket, and SignalR protocols
iTerm2 - A terminal emulator for macOS that does amazing things.