PowerShell is described as '(including Windows PowerShell and PowerShell Core) is a task automation and configuration management framework from Microsoft, consisting of a command-line shell and associated scripting language built on the .NET Framework' and is a very popular Shell in the development category. There are more than 50 alternatives to PowerShell for a variety of platforms, including Windows, Linux, Mac, BSD and PortableApps.com. The best alternative is PuTTY, which is both free and Open Source. Other great apps like PowerShell are cmder, ConEmu, Tabby Terminal and Hyper.
PowerShell is mainly a Terminal Emulator but alternatives to it may also be Shells or SSH Clients. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of PowerShell.
PuTTY is a free and open-source terminal emulator, serial console and network file transfer application. It supports several network protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection. It can also connect to a serial port.
Hyper™ is a beautiful and extensible, cross-platform terminal built on open web standards. It provides an elegant command-line experience that is consistent across all supported platforms which includes macOS, Windows and various Linux distributions like Fedora and Debian.
Cygwin is a Unix-like environment and command-line interface for Microsoft Windows. Cygwin provides native integration of Windows-based applications, data, and other system resources with applications, software tools, and data of the Unix-like environment.
iTerm2 is a replacement for Terminal and the successor to iTerm. It works on Macs with macOS 10.10 or newer. iTerm2 brings the terminal into the modern age with features you never knew you always wanted.
GNOME Terminal is a terminal emulator for the GNOME desktop environment written by Havoc Pennington and others. Terminal emulators allow users to execute commands using a real UNIX shell while remaining on their graphical desktop.