I highly recommend this post since it has the most meticulously arranged series of explanations which I look up to, as a qualified synthetic organic chemist I have no better words for compiling such a vast topic for all categories of readers (some basic knowledge of chemistry is advised but not imperative). Putting all this in words is a colosal work that ellicited my uttmost respect, please read this before making subjective rankings of any sort without reffering to the molecular binding assays data.