7. Clip (99 parts)
Clips can attach to other parts in this category such as a bar, handle, or lightsaber blade.
Clips were introduced in 1978 because they are the same connection type as the hands of the LEGO Minifigure which debuted in that year. This is when we began seeing parts with a 2.4mm diameter handle, as well as minifig accessories (which you will find in another category).
A bar (or lightsaber) can be inserted into parts with a hollow stud. That's because the hole in a hollow stud has the same 2.4mm diameter.