Applied mathematicians speak of various areas of math as tools in their toolbox, things that can be used to model various situations: differential equations, Monte Carlo simulation, statistical models, etc.

Maybe *palette* would be a better metaphor than *toolbox*. Toolbox implies that a problem has been stated and needs to be solved. A palette suggests an array of possibilities to capture some aspect of reality. Maybe *toolbox* is a better metaphor for ways to work with a model, but not for forming a model.