The main purpose of having cabinets on your island is to store one-off items, lots of pets, among others. I have a huge museum going with lots of different gear with no way to track them within the game. The suggestion is to add a feature similar to 'Try On' in the /wiki that once it is ticked would let you know whether you have that item. Not a list, per se, just a mark in the /wiki indicating that you have that item.
YouTube channel Pascalore with RPG-MO beginner videos