Historic Importance of Tin(Sn)
Some tools were made of "pure" copper. But tin was the best and only available addition to copper for strength. At the time tin was the only type of bronze. Today a variety of copper alloys are called "bronze"  that do not contain tin. Lead could possible have been available depending on time and place but it does not improve strength of copper and could actually weaken it. I see in alloy listings there are silicon bronzes ( today) that contain 1 to 2 % . Silicon was available, but it takes modern technology to alloy it into copper. Silver and gold could be added to copper ( they are all mutually soluble ) but make little increase in strength. There is a copper alloy today that contains about a quarter % of each phosphorus and arsenic ( C14200) , it is a wrought product so not available in the bronze age. The Copper Development Association  presumable has some information on the internet.