So many! Just a few that come to mind: compound interest, observation selection effect, bias, differential technological development, function, present value, correlation, subjective experience, trivial inconvenience, self-amplifying capacity, expectation, etc.

Also, many conceptual distinctions in philosophy are useful: analytic-synthetic, a priori-a posteriori, de re-de dicto, phenomenal-intentional, proximate-ultimate, intrinsic-instrumental, factual-normative, contingent-necessary, etc. Taxonomies of views in a given field, too, can be quite helpful in conceptualizing the relevant boundaries (e.g. Chalmers on views about consciousness or Miller on views in metaethics).

I guess one could say the concept of a useful concept is itself quite useful.