What is the Item Finder?
The Item Finder is a menu in your inventory toolset while building in condos. It can be used to locate items by various means. Hold your inventory keybind, Q by default, and click on the Item Finder button on the top right of your screen. You will see this menu:
You can sort the items alphabetically (note that you can rename items that are placed down), by distance, and by store you buy the items from.
A multitude of the same item is consolidated under single entries that display how many of that item there are, as long as you have the Group setting checked on the top right. Uncheck it to easily see individual items.