Some personal examples:
Dice forge has its way of handling dices that felt incredibly smart the first time I played it
Same for Codex Naturalis, I was impressed by the simple way they printed the cards to allow for modularity, obviously the game is a lot simpler than I thought but it gave me some interesting ideas with how to overlap cards
Or the boards in Fort that have this double layer so that you can nest your pizzas and toys in there, so cozy!
A tie between a D20 and the Ace of Diamonds card. The die because randomness and the card because I like to sometimes refer to my fursona as the Ace of Diamonds.