If I am interested in attach Zorro to a broker that is not currently in the list yet, like Tradovate which has a lower fees for futures trading, what can I do what shall I do to proceed?

Do I have to wait till Zorro Support whether they want to add that or not, or, is it possible that I may also contribute and work on some wrapper to make that possible?

Three methods:

1) Ask nicely for a plugin, and maybe oP group will make it for free or as a Zorro S feature. You can go here to make such requests.
2) Write a DLL yourself using the Broker Plugin API.
3) Pay someone to write the DLL for you.