I actually had to ponder this question for a while.
I'd prolly be a very lazy dragon who doesn't go out in the sun so my lair would probably be a dry cellar type deal.
On my walls: books, scrolls, paper, and maybe some art.
And my main hoard would probably be intricately carved jade and wood like mahogany or nara. And fine fabrics..
My hoard would be presented nicely, sitting on the finest cushions and rugs. I don't want it in piles, getting scuffed or dirty or, worse, stepped on.
I would've said food or tea but unless I had time magic to prevent molding and stuff I wouldn't want that. XD
Edit, idk why but I randomly thought about this thread and wanted to ad that I'd have people send me postcards.
Or maybe when I traveled I'd send myself some and have a wall just for that.
