Instant collection of huge old safety pin style horse blanket fasteners - that tiny little thing is a 'regular' size safety pin, just to give you an idea as to the scale of these pieces, largest about 4 1/2" long.
The ones made like giant kilt pins are steel, and the two with the covered heads are brass, with very worn plating or finish. All are spotted, but they work fine, and look great as a display if unusual old pieces of hardware are something you love as much as we do.
You could use these as holders for anything really, one of these is marked 'Key Tag', as shown. The points on these look a little alarming for key tags to me!