Your building shortcuts can hold inventory items as well as pieces.
In Enhanced Build Mode, open your inventory, hover an item, and press a Build Mode slot key to assign that item type to the current bar. The shortcut later finds that item in your inventory and uses or equips it. This can keep a hammer, hoe or useful consumable close at hand without depending on its inventory position. Using a combat weapon through a slot exits enhanced build mode.
You can scroll between multiple build bars by holding CTRL and using scroll wheel. There are 10 different build bars you can use.