What is a still life? The classical image is fruit or flowers. Perhaps a book on a table. That kind of carefully laid out and placed, classical and simple, sometimes with fish or fowl included.
Then of course you can have quirky things in it. I’m thinking of doing some with a plastic dinosaur. It’s about lighting and shapes. Making a pleasing or even a discordant image.
Basically it’s up to the artists ideas and feelings, you don’t have to be limited. You can be as experimental as you like.