None at the moment. I have two open rooms and I am using one for my gyroids and gems. Saying that in my older town I have a fashion room/wardrobe, gyroid room, Nintendo room and a Golden/sleek room with a snooker table, kinda like a weird gentleman's club for the very rich and tasteless lol. I haven't really styled the rooms as I am still working on some of my houses in both towns.
I always alwaysssss have used them for storage, even though I don't even use my closets that often. In my new town I may make a themed room or something
It used to be a huge storage of random unorderable stuff.. but after the update that added secret room thingy, i emptied like most of them and moved sone stuff to my new copy so it's pretty empty now..
I made a sloppy room as a little teen-hangout area with a mini arcade area and lots of band and youtuber posters I'm probably going to take it down later this week, but it was fun to make! I also have a trophy room, a picture room, and a horror room based off of the corpse party games that uses a lot of the "creepy" items!
I have a room where I showcase all the hybrid flowers I've grown. Only one left! And I have a room dedicated to all my villager pictures. And the other two are used to display all my clothing items so it's easier to make outfits. Those rooms are much happier now that you can hang clothes on the wall!
two rooms are sea themed for storing all the music box shell I have since I love listening them
for the others I'm stll thinking but I would like something dreamy
I'm probably going to take it down later this week, but it was fun to make! I also have a trophy room, a picture room, and a horror room based off of the corpse party games that uses a lot of the "creepy" items! 
