I assume you are familiar with The Practical Handbook of Plant Alchemy (recently reprinted under the title Spagyrics)by Manfred Junius?! It's just that I thought I would recommend that as another source that contains a nice amount of alchemical symbols/characters in chapter 12.
In addition... when it comes to the more elaborate symbolism of alchemy, has anyone here ever studied the courses by Adam McLean? I purchased his first three symbolism CD Roms a few years ago as well as his introductory course on studying alchemical symbolism. I am personally very fond of it so I highly recommend it. But I would really like to hear what impression others have had from studying his symbolism course as well.