There are stick pins, fibula, hinge pins, clutch backs, and many variations on each of these.
The main thing to look for is that the pin backs are made from a material strong enough to support the weight of the jewellery. If the pin back is made from sterling silver or gold it can only support light pieces of jewellery, unless it has a thicker wire than the average pin backing. If the wire is nickel or stainless steel it can be narrower in diameter and still support the weight of the decorative side of the pin without warping.
Think about the clothing you want to wear the piece on and make sure the pin going through your clothes is the right size to stay in place and not damage the fabric or knit.
’20 Tips on maintaining our Jewellery’, Gillian E. Batcher, 2013