Nevertheless I think each time there is one sound, there is one fundamental note and harmonics ?
Each time there is a periodic sound/signal, there is a fundamental and harmonics. There are proper periodic sounds (like a regularly interrupted air stream) and there are almost proper periodic sounds where higher modes of vibration are approximately harmonic, like piano strings where thicker strings exhibit some disharmonicity with higher partials being somewhat sharp of being proper harmonics. Those are pitched sounds.
But something like the crash of a cymbal or a hissing sound just does not have enough dominant frequencies to lend itself to a periodic or almost-periodic representation.
Drums tend to be unspecific enough in frequency (also depending on just how you strike them) to count as unpitched while timpani are constructed and tuned specific enough to count as pitched. That's sort of the borderline that is drawn musically.