You can make use of the intermediate level learning paths on the academy. They have sample questions at the end of each of their modules.
And as far as I know, academy team does not provide further sample questions besides those.
I took the intermediate exam quite recently and my advise for you would be to work on all those learning paths and to go over all of them before the exam.
It is against Mendix policies to share the questions or take copies of it. So no one might have it.
Follow the learning path, do lot of Mendix, focus of security is the best approach.
Nowhere on the internet. I think you will get the best information by sending a mail to firstname.lastname@example.org.