The Chinese would sometimes strap a barrel of gunpowder to the rear of an oxen, set the thing on fire, and drive the terrified creature out of the fortress hopefully to detonate among besiegers and their siege engines.

They also shot some pretty weird stuff from their trebuchets; molten iron or poison bombs with such highly descriptive names as "human excretement bomb"...

Winches, pulleys and cranes were often used wherever the know-how was available both by and against medieval and ancient fortifications - to lift soldiers to the battlements, for example, or conversely grab rams and similar siege engines and hoist them up, rendering them useless.

Sometime in the 1500s or so the English tried to give pikemen some firepower by tying a longbow to the pike-shaft. As one writing on combination weapons has it, "in the history of combination weapon the sword-cane represents sanity and the pike-longbow raving psychosis."
Needless to say, the experiment was unsuccesful and quickly abandoned.