var a = [];
$('.wikitable tr td:nth-child(2)').each(function() {
    var b = $(this).text();
    if ($.inArray(b, a) === -1) {
        if (b.indexOf(' & ') > -1) {
            for (var i in b.split(' & ')) {
                a.push(b.split(' & ')[i]);
            }
        } else {
            a.push(b);
        }
    }
});
console.log(
    a.reduce(function(a, b) {
        if (a.indexOf(b) < 0) a.push(b);
        return a;
    },[])
    .sort()
);