The Item Locator allows you to quickly find any misplaced attractions or items items in your park. It is accessible from each card in the build menu.
Select a card in the build menu, and tap on the magnifying glass in the top left corner. This sends you back in the park, at the exact location of the first building placed with the chosen card.
From there, when the building is selected, you can use the little left and right yellow arrows on the edges of the building’s menu to cycle through the other instances of the same building in your park. Note that if you only have one instance of a building, the arrows won't be there.