Head of household. Search the pre-1850 U.S. census period to see if she is named as head of household.
Military pensions. Search for military pension records from the Revolutionary War. Widows of soldiers have been eligible to receive the pensions of their husbands from the Revolutionary War forward. Women could not join the military until 1890 as nurse so you will not find wills based on their service until after this date.
Finding wills. Searching for wills by a woman can be hit and miss. If a woman died after her husband and remarried, changes are there is no will because all she owned when to her new husband. However, If she was single when she died, there might be a will.
Church records. Search to see if church records exist for the community in this time period. Usually if you find them, start by looking for the person listed as head of household in categories of marriage, christening of children, baptism of children, death of family members, etc. You may be able to find the maiden name of the wife, if the witnesses are named in the marriage. If you find a first name for the wife, search all the first names in the church records to give you suspect families where she may have been a child.
Look for same names. If you are able to find the names of children associated with the male head of household, look for other heads of household in the area with the same first name. Remember that children were usually given the name of parents. Also look at the middle names of male children. The mother’s maiden name was often preserved in the middle name.
Bible records. If you are really lucky, you may be able to find bible records. For example, the Library of Virginia has a large collection of bible from the 17-1800’s. I was able to locate a family bible that had been preserved this way.