Hi. I'm not sure what you mean with this question. All pets can be fun to dress up, you just have to find a pet (or item) you like and discover some inspiration to dress it up. Look through your pets and items, and if you see something you think is interesting look for a pet/item to match it.
For example, when I first got my green fish rat items, I immediately knew I wanted to dress up a pet with them.
I took these:

and turned them into this:

I did the same thing with a pet. I saw this pet from Halloween 2011:

And I thought she looked very much like a witch or sorceress. So I made this:

Just use your imagination, and find something you think would look cool, and do it. All pets are fun to dress up. All items are fun to use. You just gotta find your own creativity to make it happen.