Hyper - Extensible, cross-platform terminal built on open web standards.
WHMCS - WHMCS is an all-in-one client management, billing & support system for online businesses.
Penteract CMD GUI Creator - Create GUIs for command line commands. Then drag files in to get their paths.
HostBill - HostBill is a powerful and flexible, all-in-one automation, billing, client management and support platform for online businesses.
Tabby.sh - Tabby is a free and open source SSH, local and Telnet terminal with everything you'll ever need.
Blesta - Blesta is professional client management, billing, and support software.