Single bracket grouping lines of text

This can be done by using the gathered environment, like this example with a curly bracket (brace):

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath}

\begin{document}

$\left\{
  \begin{gathered}
    \mathrm{x} \\
    \mathrm{y} \\
    \mathrm{z} \\
  \end{gathered}
\right.$
\quad
$\left\{
  \begin{gathered}
    x \\
    y \\
    z \\
  \end{gathered}
\right.$

\end{document}

I can’t remember where I found this, but it was on a forum explaining how to do one bracket with multiple lines of text inside it.