\documentclass[preview,border=12pt,12pt]{standalone}
\usepackage{etoolbox,pgffor}
\edef\mylist{batman,superman,ninja turtle,spiderman,hello kitty,pstricks,tikz,}
\edef\templist{\mylist end}
\def\trim#1,end{#1}
\edef\yourlist{\expandafter\trim\templist}
\begin{document}
\foreach \x in \yourlist{\x!}
\end{document}