$ perl -MEncode -MData::Dump -
$f{$_}=encode($_,qq{\x{feff}})
  for grep/^ut/i, Encode->encodings(q{:all});
dd\%f;
__END__
{
  "UTF-16"       => "\xFE\xFF\xFE\xFF",
  "UTF-16BE"     => "\xFE\xFF",
  "UTF-16LE"     => "\xFF\xFE",
  "UTF-32"       => "\0\0\xFE\xFF\0\0\xFE\xFF",
  "UTF-32BE"     => "\0\0\xFE\xFF",
  "UTF-32LE"     => "\xFF\xFE\0\0",
  "UTF-7"        => "+/v8-",
  "utf-8-strict" => "\xEF\xBB\xBF",
  "utf8"         => "\xEF\xBB\xBF",
}