This wonderful site modestly bills itself simply as “Translations of women’s writing before 1700,” but this paragraph gives a fuller picture:
Below are links that will take you to passages from over 125 women writers. The entries are on women who produced a substantial amount of work before 1700, some or all of which has been translated into modern English. Each entry will tell you about the print sources from which the translated passages are taken; it will also tell you of useful secondary sources and Internet sites, when those are available.
They really do scour both print and the internet; I checked one of my favorite unknown women writers, Olympia Morata, and not only do they have her, their first link is to my post on her! So I heartily endorse this site (which is maintained by Dorothy Disse), and I look forward to discovering many writers previously unknown to me. (Via wood s lot.)