Something I found recently is Steve Keen's Minsky, and his book The New Economics, which uses Minsky to go through a series of simple models of the modern fiat money system.
I was going to suggest this tool too as I’m not aware of others like it.
Worth the caveat that Keen is a heterodox economist. So if you pull his off-the-shelf models you are not getting the current accepted “mainstream” theory. I don’t think Economics is a field as mature as Physics where you should have extremely strong deference to the orthodoxy based on an incredibly strong prediction record, but it’s worth keeping in mind.
Mathematical models are that, models—a simplified version of a particular phenomenon. Economic models are no different, in particular they presuppose, among other things, that economic agents behave rationally [1].
Economic “rationality” sometimes gets a bad rap, but it’s more defensible than it may appear and provides a well-circumscribed, workable general foundation to expand on. In simple versions: rational preferences (which include indifference) are transitive and complete, and people pursue these goals. That’s all. Symmetric violations wash away in the aggregate, and asymmetric can be included, e.g. as loss aversion. Criticism of “rationality” is often stuck in late 19th to mid 20th century debates that were since generally resolved.
