I make it green for an ssh session, and red when I'm root. That's it, nothing fancy.

I can recommend Starship.

If you like customizing your shell, there are really cool things one can do with zsh.

I have mine set up with suggestions to complete the name of the program, or even command line options for it.

I got different colors for Kubernetes clusters. Like green for testing cluster, yellow for development and red for production. Always taking a Quick Look before I do something

Most prompt customizers have an option for showing how long last command ran and whether it succeeded/failed or simply prompt timestamp, it's often default. I use Tide, there's also Starship and a number of others. You can also roll your own ofcourse.

A person in this thread already recommended having different colors for different conditions like ssh and running as root, I havent seen anyone mention this specifically but you can determine if the current working directory is writable with something like [ -w "$(pwd)" ] and set the color to red or print a symbol if it doesnt return true.

Also I recommend putting all the code and logic for your shell prompt in a shell function, and using a substitution shell to put it into the PS1 variable like this:

__shellprompt ()
{
    if [ "$(id -u)" = 0 ]; then
        local PROMPT_EMBLEM='#'
    else
        local PROMPT_EMBLEM='$'
    fi
    printf "%s" "$(whoami)@$(uname -n):$(pwd)"
    printf "\n%c " "$PROMPT_EMBLEM"
}
PS1='$(__shellprompt)'

Now this is just a really barebones example, there is a whole lot more you can do like passing in the last exit code through the argv of your shellprompt function like this PS1='$(__shellprompt $?)' and like print it out if its non-zero so you wont have to like echo $? to see if the last command failed, but you should be able to still do this. In my testing, running the shell prompt function in the subsitiution shell didnt effect the $? variable.

In my first comment on another thread about shell prompts, I posted my full shellprompt, it is slightly outdated (I just changed hostname to uname -n), if you cant find it feel free to send a message or just ask, and I will send you the code.

Powerline!

I customized mine to show git branch when in a git project directory.

Use PS1="▌\t▐\n\w→" to display your local time each time you press enter. And make aliases of lengthy commands such as alias internettest="curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python -" (You need to install python to run this.)