I need supplemental health insurance to cover hospital visits, x-rays, ER.

My husband got a new employer recently and his employer basic plan is bare bones. It has a 0% deductible and It covers all of:
Preventative care, urgent care, basic prescriptions, provider specialists, primary care for illness/injury, lab tests.

But anything dealing with hospital care or care in a hospital facility is not covered whatsoever. Emergency care, x-rays, any sort of imaging. My whole family is in need of PT care in some form so I am trying to figure out how we can make sure we’re covered. Also want to make sure my kid is covered for anything that can arise from getting injured as kids do or very sick.

Is it possible to get some type of supplemental insurance to cover these? I know we could use the help of x rays and imaging because my husband has a brachial plexus condition that needs to be re-evaluated and will need some tests and imaging done to see where his condition is at, at this point.

We haven’t enrolled into his employer’s basic plan yet but are considering it since it’s decent for barebones basic care, although it doesn’t cover any vision or dental.