Tracking down elusive female ancestors is a task that all of us have faced at one time or another. We know it can be challenging.
If you have been faced with such a task, you may want to look at a Family Tree Magazine article by Lisa Alzo. In it she gives some time-tested sources and strategies that may be just what you need. I suspect that none of the records she talks about will be unknown to you, but a review of them may be helpful. The true value of the article in my opinion is not the list, but the explanation she gives on why each group of records may be of value.
Read the article at Best Records for Finding Female Ancestors - Family Tree Magazine