While working on his soldering iron driver Arhi did some research on Solomon soldering irons (machine translation). Solomon is one of the largest OEM manufacturers of soldering irons, it can be bought under various names like Nedis, Elanco, Tenma, etc. Replacement irons are cheap, under $16, making them perfect for his driver.
The most common types are the SL and HQ. The SL is a older model where the tip is placed into the heater, while the newer HQ irons have the tip slide over the heater and have a greater thermal mass. Arhi provides the standard Din-5 pinout used, as well as pictures of both irons broken down to their components.