The matching in list context returns the matching groups ($1, $2...), which are created by parentheses in the regular expression. You should add another pair of them that spans the whole macro, you should also turn the inner group into a non-matching one so it doesn't pollute the results:

#!/usr/bin/perl
use warnings;
use strict;

my @inarr = (
             'stuff{tag}<igo;123>stuff<ig;abc>',
             '<igt;ddd>stuff blah {foo}',
             'stuff blah foo <igxo;dsldkd.eps>',
             '<igt;aaa>stuff blah <igx;hhh>',
            );

my $re = qr/( < (?: ig | igt | igo | igxo ) ; .+? > )/x;
for my $lin (@inarr) {
    my @g = $lin =~ m/$re/g;
    print join ' ', map "[$_]", @g;
    print "\n";
}
[download]