Samsung makes some of the best hardware, but they have excellent software features or add-ons, too. This next thing is more of a helpful feature than a "cool" one. That said, you'll be thankful you have it.
With the Galaxy Note 9 One UI Android Pie update, Samsung added a recycle bin to the camera gallery. Some regions it's labeled as a Recycle Bin, while other areas it's listed as "Trash".
That means when you throw away or trash photos, they're temporarily saved to a recycle bin. I can't remember how many times I've deleted something then WISHED I could get it back.
If you didn't enable the trash/recycle bin when the feature arrived in Pie, just open the camera and go to settings. This'll save you in a pinch, one day, trust me. Previously Samsung had a "cloud trash" option, but this temporarily saves photos on your phone in case of emergencies. They auto-delete after 15 days, which is long enough for me.
It's one more cool thing Samsung thought of to make life's easier for owners.