Ear plugs to block noise

On the basis that headphones/ear phones are specifically prohibited, I would say that non-electronic items to put in your ears are permitted. I would advise that you have them displayed before the exam starts/ask the invigilator for permission, so you aren’t interrupted during the exam.

Agreed, but remote exams should be sat in a quiet location, unlike an exam centre. In an exam centre an invigilator can see if ear plugs are foam. And there’s no harm in asking before using.