Comments
While it's hard to disagree that people should be familiar with the basics of economics, statistics, &c. I am not excited by the spirit of the question and the references to 101 materials.
First, I expect research scholars (and forum readers) to have quite a bit of shared knowledge about topics useful for EA. But more importantly, such advice doesn't make use of distributed coordination [1] and doesn't expand our aggregated knowledge. So I would be much more excited for general recommendations with "randomness," which decorrelated the individual decisions.
For example: read a bunch about a few historical periods of your interest. No hurry with that; maybe, don't solely read about the West; maybe, read something by anthropologists or econ historians. Doing so will expand the group's intuitions about social movement, technological development, causes of war/conflict, power &c.
[1] A similar problem arises with a naive interpretation of 80K career advice (before stronger emphasis on personal fit): people would concentrate on the explicitly outlined paths without accounting for others doing the same.
A slightly boring answer: I think most people should at least partly read something that overviews common theories and frameworks in normative ethics (and the arguments for and against them) and something that overviews core concepts and principles in economics (e.g. the idea of expected utility, the idea of an externality, supply/demand, the basics of economic growth, the basics of public choice).
In my view, normative ethics and economics together make up a really large portion of the intellectual foundation that EA is built on.
One good book that overviews normative ethics is Shelly Kagan's Normative Ethics, although I haven't read it since college (and I think it has only a tiny amount of coverage of population ethics and animal ethics). One thing I like about it is it focuses on laying out the space of possible ethical views in a sensible way, rather than tracing the history of the field. If I remember correctly, names like Aristotle, Kant, etc. never show up. It's also written in a very conversational style.
One good introductory economics textbook is Tyler Cowen's and Alex Tabarrok's Modern Principles of Economics. I don't know how it stacks up to other intro textbooks, since it's the only one that I've read more than a little of, but it's very readable, has very little math, and emphasizes key concepts and principles. Reading just the foundational chapters in an intro textbook, then the chapters whose topics sound important, can probably get most people a decent portion of the value of reading a full textbook.
I remember that reading up on normative ethics was one of the first things I focused on after I had encountered EA. I'm sure it was useful in many ways. For some reason, however, I feel surprisingly lukewarm about recommending that people read about normative ethics.
It could be because my view these days is roughly: "Once you realize that consequentialism is great as a 'criterion of rightness' but doesn't work as 'decision procedure' for boundedly rational agents, a lot of the themes from deontology, virtue ethics, moral particularism, and moral pluralism become relevant again - through a backdoor as it were. It is therefore kind of misleading to think of consequentialism vs. deontology vs. virtue ethics as alternative theories, which however is the way normative ethics is typically presented in the analytic tradition."
Fortunately, if I remember correctly, something like the distinction between the true criterion of rightness and the best practical decision procedure actually is a major theme in the Kagan book. (Although I think the distinction probably often is underemphasized.)
I agree there is something to this concern. But I still wouldn't go so far as to say that it's misleading to think of them as alternative theories. I do think they count as conceptually distinct (even if the boundaries are sometimes a bit muddy), and I think they do sometimes have different implications for how you should in fact make moral decisions.
Beyond the deontology/consequentialism debate, I think there are also relevant questions around demandingness (how strong are our moral obligations, if any?), on the nature of well-being (e.g. hedonistic vs. preference-based vs. objective list theories), on the set of things that count as morally relevant consequences (e.g. do things beyond well-being matter? should we care more about totals or averages?), and so on.
Yeah, I think these are good points. I also suspect that many deontologists and virtue ethicists would be extremely annoyed at my claim that they aren't alternative theories to consequentialism.
(Though I also suspect that many are somewhat annoyed at the typical way the distinctions between these types of theories are described by philosophers in a broadly consequentialist tradition. My limited experience debating with committed Kantians suggests that disagreements seem much more fundamental than "I think the right action is the one with the best consequences, and you think there are additional determinants of rightness beyond axiology", or anything like that.)