I've got a five burner Lamona gas hob and the control knobs/dials have broken as they are a terrible design.  As they only seemed to sell these in packs of four, I decided to 3D print some simple replacement versions.

Word of caution, PLA doesn't cope well in heat so would recommend keeping an eye that they don't melt from the peripheral heat from the hob.  Although that said mine have been fine!