I think the intent of the thread is to talk about games specifically designed to be toolkits, like FUDGE and Cortex and perhaps (depending on where one draws the line) GURPS, Hero and Savage Worlds.Eg D&D d20's, level grind etc., it's the whole osr. However, the definition of toolbox is vague enough to be meaningless, I have seen it argued over T5, and Cepheus Engine. Mostly I have found in 45 years of playing is that most people play a setting, not mechanics, and there are going to be intrinsic styles of play. Class roles? Characters as individuals?