In the Pokémon Crystal Diamond Brilliant Pearl interactive plaza, players can only bring certain Pokémon to enter the walk, and when certain conditions are met, they can get ornaments or tree fruits. Below is a list of items available from the Pokémon Crystal Diamond/Brilliant Pearl interactive plaza compiled by the "Ray Break Gas Pack" for your reference.
Pokémon can be carried in the interactive plaza
After your first visit to the square, you can unlock the walking function
After your first visit to the square, you can unlock the ability to walk with Pokémon outside the square. Unlike inside the square, there are no restrictions on walking outside the square, and you can even bring the legendary Pokémon, so choose your favorite Pokémon to take a walk with.
Interactive Plaza is available for items
Tree fruit can be picked up
Pokémon walking together in the interactive plaza may pick up tree fruits, stickers, and other items, even if they are not [picking] characteristics. The types of tree fruits that can be picked up cannot be identified outside the square, so if you want to collect them, you can only pick them up continuously inside the square.
The fruits that can be picked up are: jade fruit, yue bamboo fruit, dan fruit, lemon fruit, spiny horn fruit, coconut fruit, guaxi fruit, golden pillow fruit, indigo fruit.
Drop items
Don't forget to pick up dropped items. The locations are as follows:
Trick Learner 43: Central Front
Trick Learner 45: Central Deep
Talisman Gold Coins: Deep on the right in the rocks on the left
Monster Slate: Deep on the right in the rock on the right