The most valuable stuff in my safety deposit box are old photos and photo negatives. Many years ago a house in our neighborhood was gutted by fire and my wife and I decided that the worse thing in a tragedy like that would be to lose all your photos. We started to gather the photo negatives of all our kids pictures and other family photos we would never want to lose and store them in our safety deposit box. I did some research and even so called home fire safes are designed only to protect paper and things like photo negatives would likely still be melted. This is also true for digital media like CDs and flash drives. Off premise storage in a bank vault is a safer option.
Your digital photos are especially vulnerable as your computer could crash or be infected with viruses or malware that could destroy your photos. Online cloud storage is cheap or even free, but copying your important photos to a flash drive that you store in your safety deposit box is cheap insurance too. Note CDs/DVDs are a dying media and backing up your photos to them might give your grand kids or great grand kids a lot of regrets as there may no longer be the computer equipment to access them in 50-100 years. Ditto for those 8mm/super8mm and VHS home movies.
I have photo negatives and memory chips for more recent photos in my safe deposit box.. Takes up the bulk of it actually.