Susan B. Anthony.
As to the women, I have a recollection at there was an idea born out of feminism that promoted the use of initials by women (and perhaps everyone) so that names were de-gendered. Thus (possibly) KD Lang, or the relatively obscure VS Brodie.
Does anyone else recall this? Seems to have gone out of fashion.
Plenty of historical Jewish sages are known by their initials. For instance, Maimonides, the great medieval philosopher, scholar and physician, is largely referred to in Hebrew as “the Rambam”, from the initials of his full name and title, Rabbi Moshe Ben Maimon.
You still see it with writers - which is why I automatically assume that any contemporary writer who uses their initials is a woman.
Surprised nobody’s mentioned W.H. Auden yet.
I think that is because in the OP I was initially asking for examples of figures outside of the arts?