Christmas Gifts Adults Could Get for Parent (Stock, Investing)?

[Casby Bias]

Super long shot here, but I was wondering if there was any advice out there as to what would be a good tangible Christmas gift for an adult to get a parent who is into investing, real estate, and individual stocks.

My dad already has a number of stock market and investing books already. I also don't have the money to buy him a share of stock that he would want at this time (e.g., Tesla).

I’ve considered getting him a stockpile gift card to give him a certain percentage of a Tesla share to help. However, after researching, I see it's not the best idea, ha ha. 

Please let me know if you have any ideas: thank you!