Who were the major innovators of new kinds of syllogisms (i.e. introduced disjunctive syllogisms, etc) in the ancient and medieval periods aside from Aristotle, Theophrastus, the Stoics, and Goclenius?
Probably the major (non-ancient) innovator of logic pre-Boole/Frege was Peter of Spain. He lived during the 13th century and wrote the Tractatus. This was not only a rehashing of ancient logics, but was also the basis of a tradition that would last almost 600 years. Since the Tractatus was ubiquitously used as a logic textbook for centuries, I would say that Peter of Spain probably made a more lasting impact on the logical landscape than Aristotle himself.
To find out more, I strongly suggest reading Peter of Spain: Summaries of Logic. It is written by three heavy-weights of Medieval philosophy: Calvin Normore, Brian Copenhaver, and Terrence Parsons. For what it's worth, I've had the honor of taking classes with all three of them and saying they are brilliant is an understatement.