With the release of V2 of the Google My Business API, Google simultaneously released categories for each of the 135 countries currently supported by the GMB. I noted it at the time but it was lost in the article but I wanted to be sure that folks so these categories and downloaded them if they needed to.
The category files list all of the business categories used by Google My Business. Download category files for the countries in which you are interested in creating locations. Each country has a different set of valid categories.
The list of available categories may change at any time.