The idea is to have a Multiple Select Drop-down, which can enable a form visitor to select multiple options for a property by clicking on a dropdown and searching for an option. This would essentially be an altrenative for Multiple Checkbox Field Type, for when there's too many options in the property.
I've recently faced this issue, where I have a Contact Property field with about 250 different options, with the ability to have multiple options associated to the property. I need to insert this Property into one of my forms, and I find that having this property as a Multiple Checkbox means that the form becomes extraordinarily long, and I have to make the user scroll through each and every option to find the ones relevant to them, along with scrolling through all the 250 options to get to the next form field. This makes for an incredibly bad user experience on the form, and I'm bound to have an insane bounce rate due to this. There seems to be no other usable alternative as of now. I'm using a multi-select dropdown in my Jotforms at the moment. As much as I'd love to move all my forms to Hubspot, the lack of this field type makes it quite difficult for me.
The form I'm using now looks like this: