Save favourite build pieces to your own building shortcuts.
While Enhanced Build Mode is active, hover a piece in the build menu and press a Build Mode slot key to save it. Press that key while building to select the saved piece and equip its required tool from your inventory. There are ten bars of ten slots; hold the Switch Build Bar Modifier and scroll to cycle bars. By default the slots use 1 through 0 and the bar modifier is Ctrl. Assignments are saved separately for each character.