Linux

Nushell

Bash, zshell, BusyBox....you don't really need anything else

oksh

I use mainly fish and occasionally nushell.

Bash. By default it might seem less featureful than zsh.. but bash is a lot more powerful and extensible than some give it credit for. It might be more complex to set it up the way you like it, but once you do it, that configuration can be ported over wherever bash exists (ie. almost everywhere).

Bash is my favourite one, second to it being Fish

zsh because I've been using it since college and I don't like change

I have been enjoying fish a lot over the last few months, but I generally try to use Bash, it makes cross-*NIX administration that much easier.

Bash as it is what I'm most familiar with. Having an eye out on the https://amber-lang.com/ that compiles to bash for future scripting purposes.

Zsh with powerlevel10k + a few plugins

Bash, just because everything else already uses it. That and bashisms have infected nearly all of my scripts as I clumsily bump into the limitations of POSIX string manipulation.

I have found some very fun things with sed branching patterns as a result of these limitations though...

https://www.gnu.org/software/sed/manual/html_node/Branching-and-flow-control.html

xterm+zsh

PowerShell, with zsh being a close second

POSIX on servers, thinking of switching to POSIX on desktop but that's a bit awkward

Bash is my login shell, but I have fish set as the default shell for alacritty

zsh with grml config because I'm too lazy to make my own config.

PowerShell, because of autocomplete and shift+arrows select.

While fish is easy to set up, I can't even be arsed to do that most times, so bash ends up being the one I use most.

xterm, because shortcut keys do what they are supposed to.

Edit:

Bash because it's default.

I have customized ZSH to be very similar to Fish