PuTTY - Popular free terminal application. Mostly used as an SSH client.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
MobaXterm - Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more
AppDynamics - Get real-time insight from your apps using Application Performance Management—how they’re being used, how they’re performing, where they need help.
iTerm2 - A terminal emulator for macOS that does amazing things.
Zabbix - Track, record, alert and visualize performance and availability of IT resources