I had earlier searched for resources specific to symbols/icons used in cultures surrounding Israel, and also in the early Christian era before Constantine. Both are difficult to search for, due the 'sounding brass' of every other kind of symbol (or cymbals).
http://www.amazon.com/Symbolism-Biblical-World-Ancient-Iconography/dp/0816403538
This is a german volume, translated to english, written by Othmar Keel (1972). It concentrates on Psalms, though the OT reference list is maybe half Psalms, and other books eg Job. The imagery is primarily egyptian, though again, maybe half is other ancient cultures. Each page (350 before notes) has 2-3 images being discussed. Image grouping is by general area ... cosmos, destructive forces, temples, etc. The author's wife inked the images, which include their source, so they're easier to make out. All are back-referenced.
http://www.amazon.com/Ante-Pacem-Archaeological-Evidence-Constantine/dp/0865548951
This was written in 1985 and updated 2003, author Graydon Snyder. The discussion is excellent on how imagery meaning is guessed at, with the author being on the conservative side of guesswork. He then goes over 12 key symbols and also pointing to other reference works. Next, he discusses the symbols as they appear ... pictorial, buildings, inscription/graffiti, and papyri (all with illustrations). About 300 pages before notes. The Christian papyri discussion is interesting, relative to the greek not matching the NT koine or apostolic father usage. He does use some of Ramsay when in Asia.
Both authors are pretty tight with their discussion ... no layers of assumptions. I doubt either would be picked up by Logos due to limited market (Keel), or heavy mixed fonts (greek, latin, syriac, etc for Snyder). But both are excellent for quick reference. I made this thread, mainly for future Logosians seeking symbol references. Save time with klanging bells.
BTW, BAR's book section often has hard to find book reviews in the back-issues. That's how I found these.
