I have written before about using guardianship records for genealogical research. Most often, we use these records to find out who became the guardian over minor children after our ancestors died.
Less often, we will check those records to see for whom our ancestors were guardians. Since guardians were often close relatives, this can be a clue about the ancestor’s family. If guardianships are indexed, that is usually by the (deceaded) parents only, not by guardian, so this may require turning the pages to see what is there.