It may seem strange, but something as simple as some hotel toiletries can be the best souvenir.
I still have my Mickey Mouse soap from the Old Key West Resort in Disney World, monoi oil from the Sheraton at Tahiti, and love using the spa quality Honey Mango Body Lotion from the Grand Wailea in Maui.
You don’t have to feel like you’re stealing as hotels want you to take those toiletries in your room, so you’ll remember the great time you had at their hotel. Plus, you paid for it in your room rate.