These are three size S collars made for greyhounds. Same model, same 3/4" stainless steel buckle.
The first one is a black on black combination with silver stitchings. It measures 2" in the wide part:
The second one is black with conker leather padding and black thread, 2" wide:
The last one is made with hazel leather with caramel padding and brown linen thread. Wide part measures 1" 5/8.