my @preferred_sans_families = (
    'Special Sans',
    'DejaVu Sans',
    'Verdana',
    'Helvetica',
);

my %all_families = map { $_ => 1 } $mw->fontNames;

my $found_sans_family = first { $all_families{$_} } @preferred_sans_families;

my $sans_font = $mw->fontCreate(... -family => $found_sans_family ...);