Mostly unknown early pioneers
Most of the large (and many small) Dental Mfg. Companies.
The common planeline articulators were (and are) the most widely used articulators. The variety of style and design seems to be almost endless. Here are just a few examples. The first improvement on the simple hinge was the adjustable upper member. This was quickly followed by a posterior vertical stop and provisions to allow for more vertical height. Many other adjustment features were added, probably to aid in the reaction of clinical errors.
Dr. Edgar N. Starcke's articles in the Journal of Prosthodontics have more information on the history of articulators.