Blocking free email addresses in the HubSpot/WP plugin
This article should help you out - https://knowledge.hubspot.com/articles/kcs_article/forms/block-form-or-pop-up-form-submissions-from-... . In short, there is nothing in the plugin that does this for you, as this is done in the form setup within Hubspot.
However, I would strongly advise against enabling this feature and do so for every client I've worked ever worked with. At the very least, what I recommend doing is to setup a workflow for someone who gives you an email address from a free provider and try to entice them to want to give you a different address. As a consumer, I may have a free account where I like marketing emails to go especially if I fear that I may get a lot, but I may be willing to share my work address for more personal communications.
Completely agree with @Ben_M .
You can see how to set up a list of all free email providers on this community thread and build your workflow on that list.