I'm so sorry! As I'm reading this now, it's really interesting because today, August 5th of 2022, was the day we had to put our cat down

It's exactly one year since his passing. He was a great cat and we have many fond memories of him but the whole process was and still is difficult. I still think about him alot. He name was and is Beeboo. We love you Beeboo. We really did and I'm so sorry we had to put you down.
For our cat, we kept his collar I got him (although he never wore it because the person he hung out with the most would always take it off haha), we kept his brush, the cup he would drink out of, my partner made a charcoal drawing of him, and we had him cremated. His ashes are in a little wooden chest with his paw print is imprinted on a clay decoration.
I don't know if your cat had some favourite items or a favourite toy that you could keep of him. Beeboo wasn't
much of a play with toys kind of cat. You don't need items of someone who has passed to remember them however. I see you have a good amount of pictures of Cole, maybe you could make a collage out of all the pictures you have? Do whatever you feel is best that you, your cat, or both of you would appreciate and cherish.
Sending you good, peaceful, and healing energy <3