tikz array lookup

See “array operator” in the TikZ/PGF manual, page 927

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}
\newcommand{\myarray}{{"foo","bar","baz"}}
\begin{tikzpicture}[font=\sffamily]
  \foreach\Color [count=\k] in {red!90!black, green!50!black, blue!90!black}
  {
   \node[color=\Color] at ($(0,\k)$){\pgfmathparse{\myarray[\k-1]}\pgfmathresult};
  }
\end{tikzpicture}
\end{document}

Arrays are indexed starting from 0

An alternative to array could be using two variables in foreach.

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}
\begin{tikzpicture}[font=\sffamily]
  \foreach \color/\t [count=\k] in {red!90!black/foo, 
            green!50!black/bar, blue!90!black/baz}
  {
   \node[color=\color] at ($(0,\k)$){\t};
  }
\end{tikzpicture}
\end{document}