For years I've been saying I need 2 car horn tones.
One, for when I see 'ol Jimmy on the street and "beep beep! hi Jimmy!" The other, for when "YOU ALMOST WRECK INTO MY JEEP BECAUSE YOU'RE TEXTING AND DRIVING."
This dude has customized his car horn to play three different sounds. The main sound is a courtesy honk, for non-emergency scenarios - which in my opinion, is the only additional horn you need.
He teaches you how to install too, kinda.