Global variable Array

You could use pgffor for that.

\documentclass[a4paper,twoside,12pt]{article}
\usepackage{pgffor}
\usepackage{xcolor}
\begin{document}
\def\ArrayNames{{"koala","duck","marmot","penguin","bear"}}
\def\ArrayColors{{"gray","yellow","blue","red","brown"}}
\begin{enumerate}
\foreach \X in {0,...,4}
{\pgfmathsetmacro{\myname}{\ArrayNames[\X]}
\pgfmathsetmacro{\mycolor}{\ArrayColors[\X]}
\item \textcolor{\mycolor}{\myname}}
\end{enumerate}
\end{document}

Or with an external file (which I create here for the convenience of others in the MWE, but you may drop the filecontents stuff as long you have a data file).

\documentclass[a4paper,twoside,12pt]{article}
\usepackage{filecontents}
\begin{filecontents*}{myarrays.tex}
\def\ArrayNames{{"koala","duck","marmot","penguin","bear"}}
\def\ArrayColors{{"gray","yellow","blue","red","brown"}}
\end{filecontents*}
\usepackage{pgffor}
\usepackage{xcolor}
\begin{document}
\input{myarrays.tex}
\begin{enumerate}
\foreach \X in \ArrayNames
{\foreach \Y [count=\Z starting from 0]in \X 
{\pgfmathsetmacro{\mycolor}{\ArrayColors[\Z]}
\pgfmathsetmacro{\myname}{\ArrayNames[\Z]}
\item \textcolor{\mycolor}{\myname}}}
\end{enumerate}
\end{document}

And of course you can install any mapping. Here is an example (in which I assume you already have created myarrays.tex, if not uncomment the corresponding lines).

\documentclass[a4paper,twoside,12pt]{article}
% \usepackage{filecontents}
% \begin{filecontents*}{myarrays.tex}
% \def\ArrayNames{{"koala","duck","marmot","penguin","bear"}}
% \def\ArrayColors{{"gray","yellow","blue","red","brown"}}
% \end{filecontents*}
\usepackage{pgffor}
\usepackage{xcolor}
\begin{document}
\input{myarrays.tex}
\pgfkeys{/pgf/declare function={mymap(\x)=int(mod(1+\x*\x,4));}}
\begin{enumerate}
\foreach \X in \ArrayNames
{\foreach \Y [count=\Z starting from 0]in \X 
{\pgfmathsetmacro{\mycolor}{\ArrayColors[mymap(\Z)]}
\pgfmathsetmacro{\myname}{\ArrayNames[\Z]}
\item \textcolor{\mycolor}{\myname}}}
\end{enumerate}
\end{document}

As you can see, this function is chosen such that it distinguishes between birds on the one hand and mammals and beings on the other hand.

Trivial with listofitems.

\documentclass{article}
\usepackage{listofitems,xcolor}
\newcommand\ArrayNames{Name1,Name2,N3,N4,N5,N6,N7,N8,N9,Name10}
\newcommand\ArrayColors{red,blue,cyan,cyan!50!red,red!50,
  purple,green,yellow,blue!50,magenta}
\readlist*\arrayname{\ArrayNames}
\readlist*\arraycolor{\ArrayColors}
\begin{document}
\begin{enumerate}
\foreachitem\x\in\arrayname{\item \textcolor{\arraycolor[\xcnt]}{\x}}
\end{enumerate}

\textcolor{\arraycolor[4]}{\arrayname[9]}

\textcolor{\arraycolor[5]}{\arrayname[8]}
\end{document}

You can have files with the following structure

\colorlist{
  {red}
  {green}
  {blue}
  {green!40!yellow}
  {-green!40!yellow}
  {rgb:-green!40!yellow,3;green!40!yellow,2;red,1}
  {red>wheel,12}
}

It would also be possible to have the simpler structure

red
green
blue
green!40!yellow

- green!40!yellow rgb:-green!40!yellow,3;green!40!yellow,2;red,1 red>wheel,12

if preferred. Then in the document you call

\assigncolors{<filename>}{<list of names for the colors>}

Here's the code, using filecontents for making the example self-contained; the name for the color list file can be whatever you prefer.

\begin{filecontents}{\jobname.colors}
\colorlist{
  {red}
  {green}
  {blue}
  {green!40!yellow}
  {-green!40!yellow}
  {rgb:-green!40!yellow,3;green!40!yellow,2;red,1}
  {red>wheel,12}
}
\end{filecontents}

\documentclass{article}
\usepackage{xcolor}
\usepackage{xparse}

\ExplSyntaxOn
\NewDocumentCommand{\assigncolors}{mm}
 {% #1 = file name, #2 = list of names
  \clist_set:Nn \l__tisaigon_colornames_clist { #2 }
  \file_input:n { #1 }
 }
\NewDocumentCommand{\colorlist}{m}
 {
  \int_zero:N \l__tisaigon_colornames_int
  \tl_map_inline:nn { #1 }
   {
    \int_incr:N \l__tisaigon_colornames_int
    \colorlet
     {
      \clist_item:Nn \l__tisaigon_colornames_clist { \l__tisaigon_colornames_int }
     }
     {
      ##1
     }
   }
 }
\clist_new:N \l__tisaigon_colornames_clist
\int_new:N \l__tisaigon_colornames_int
\ExplSyntaxOff

\assigncolors{\jobname.colors}{
  color1,
  color2,
  color3,
  header,
  body,
  footer,
  fancy,
}

\begin{document}

\textcolor{color1}{Abc}

\textcolor{color2}{Abc}

\textcolor{color3}{Abc}

\textcolor{header}{Abc}

\textcolor{body}{Abc}

\textcolor{footer}{Abc}

\textcolor{fancy}{Abc}

\end{document}