A miniature flashlight with a Mickey head sticker on it. Has gone on many cruises with me since. One time someone made individual ornaments for us with images from our listed favorite characters.
My wife has made all kinds of things - Disney trivia cards on a metal hook, luggage tags (two types now), towels where she sews on a Disney strip of fabric (also received once which gave her the idea), personalized t-shirts (when we did the exchange with just friends), etc.
We're likely to pass on doing FE on our Jan 2023 cruise. Our prior cruise was Dec 2022 and we went crazy, giving stuff almost every day since it was around Christmas time. I splurged and got everyone the Jim Shore Mickey Mouse sailor. Each person got a personalized luggage tag and hand towel from my wife; made with her sewing machine using Disney fabric. I did the flashlight thing that I enjoyed mentioned above. Each person got a cruise themed bookmark and some Disney themed magnets. The kids we also gave Disney toys, candy, activities, those expandable rags with Disney characters.
One of our assigned cabins ended up doing nothing, another gave some stickers, and the other items were non memorable. We taught the girls it's better to give than receive and they had a blast daily giving items out, but given the effort my wife put into individually sewing items (easily 20-30 hours of work), sort of soured me. We're more likely to bring items and Pixie Dust them then sign up this go around.