You name it! We did our first FE gift exchange in December and it was a lot of fun. Some people do one gift per stateroom, others do something for the kids and something for the adults.
We gave out:
Survival kits to each room: ziplock bag including bandaids, safety pins, lens cleaning cloths, anticbacterial hand wipes, small pack of tissues, highlighter and post it pad. We also included a UCONN magnet and a CD or cruise music that I made, along with some mini bags of M&Ms and skittles.
The kids in each room got stickers and pencils.
We received a TON of gifts, including:
Artificial wreath decorated with Disney things
pirate themed items (bandanas, tattoos, necklaces, shot glass)
"paperbag" scrapbooks - so very cute!
DD received 2 sets of barrettes with "crystal" mickey heads that someone made
pencils, candy, Christmas ornaments from the state where people lived, crayons, card games, magnets, "nip" bottles, small candle, Disney magic towels, etc.
There are many very crafty/creative people on the board that make something for everyone/room (like the scrapbooks) and others buy little gifts. It's not the amount you spend or how much you give, it's just so much fun to come back to the room and see your FE full of gifts!
I shipped my gifts to our hotel (we were in WDW for 5 days prior) and also included an extra carryon bag that I used to get them onto the ship. Then, that bag was used to bring all our gifts and souveniers back home. Be prepared...you will be overwhelmed by what you receive!
We had 16 rooms in our exchange last year. Some people have had a lot more and other groups will split up the list so you aren't buying for a gazillion people.
Find your meet thread for your cruise and I'm sure there is someone already collecting everyone's info for the FE exchange. There are also some great threads about homemade FE gifts on the board. Have fun!