That's actually std::optional, minus the nothing/just notation? Indeed more people should use things like this. Reminds me of a similar concept I also have wrappers for: instead of manually having to compare the results of std::find etc against range.end() all over the place, the result is basically in a small container which has both the iterator returned and the end of the range. So I write

    const auto result = alg::find( range, pred );
    if( result )
      doStuff( *result ); //*result is reference to found element

instead of typcial

    const auto end = range.cend();
    const auto result = std::find( range.cbegin(), end, pred );
    if( result != end )
      doStuff( *result );

Not that much of a gain, but once used to it I could never go back. And I realize now this could actually just be rewritten using your maybe class or std::optional.