I would like to be able to make limitless tickets available. Unfortunately when I set it to 0 (which I was hoping mean limitless) it causes an NaN error when folks click to add.
Leaving the field blank will enable you to sell an unlimited number of tickets:
I will say that the UI is not super clear once the ticket is saved because it will always appear in the reports that there is a Zero quantity in stock, but there will indeed be unlimited tickets available.