Thanks to Kenneth Marks for making this information available in his Blog: The Ancestor Hunt. The link below will take you to a page with a list of links to wills and probate records online. The list is alphabetical by state. You have to scroll down the page a bit to get to the list. The list is mostly links to records available on FamilySearch.org.
Preceding the state list are some links to articles about the value of probate research.
It is worth checking some of the tabs available at the top of the landing page. Specifically, the tabs titled "Resources," "Blog," and "More." They will reveal that Kenneth is offering a wealth of research assistance in a variety of topic areas.
Check it out at: https://theancestorhunt.com/probate-and-wills.html