Here's a helpful research hint I've recently learned from two esteemed genealogists. Because I've been doing genealogy for a while, I have shelves full of books. So when those books came out in searchable CD format, I didn't buy them. I already had the content in print, plus I had a mac and the CDs were, without exception, for PC computers. To this day, I can only use CDs that have PDFs on them, like the MOCA compilation of Maine cemeteries.
In any case, if you have either the CD of Torrey's New England Marriages to 1700 or Savage's Genealogical Dictionary of New England, you can search either of these sources by first name without a surname. You can therefore make a searchable list, most likely of women, with unusual surnames that might be your ancestor's wife. The Great Migration Series (now in nine volumes) each has a given name index which I use. It was that way I noted the infrequent use of the name Benajah. If I had used Savage I would have discovered one more use of Benajah. Likewise, after I submitted my most recent article for publication, the editor noted a potential Deliverance after searching Torrey's on CD.
This type of search capability may knock down a few more brick walls in the future. I've also used the NEHGS Database of Mass. Vital Records to 1850 for such searches. By searching even a common name, such as Elizabeth and, limiting the search to a given town (in my case Ipswich) and for the years during which she was likely born based on her marriage date and when she had children, I had a researchable list of a dozen or so Elizabeths. In my case, I married them all off to other men, but it was worth a try.