LEGO Supplementaries were sets released during the early days of the LEGO system. These sets were designed to supplement and expand upon the building possibilities of existing LEGO sets. Instead of being complete stand-alone models or kits, Supplementaries provided additional bricks, special parts, wheels, windows, doors, gears, or even motors. These sets were especially useful during an era when LEGO's product line was simpler and less specialized than it is today.
1974 LEGO Sets
1974 saw the Universal Building Set broaden parts variety and color, while large ‘Family’ (maxi) figures and the Homemaker line brought interiors and furniture to the forefront. Early mechanical elements began laying groundwork for later Expert Builder/Technic. Trains continued to evolve on 12V in Europe, refining the system ahead of the 1980s expansion.