paste is one of those tools nobody uses [1]. It puts two file side by side, line by line.
One application for this came up today where some tool was called for several files at once and would spit out one line by file, but unfortunately not including the filename.
$ paste <(ls *.rpm) <(ls *.rpm | xargs -r rpm -q --queryformat '%{name} \n' -p)
[1] See "J" in The ABCs of Unix