Sub ГенераторИО()
Application.ScreenUpdating = False
Dim Name As String, Fam As String
Dim NameRow As Long, FamRow As Long

'отсюда код https://www.planetaexcel.ru/forum/index.php?PAGE_NAME=message&FID=1&TID=94211&MID=s
NameRow = Sheets("Данные").Cells(CInt(2 + 53 * Rnd), 2).Row
FamRow = Sheets("Данные").Cells(CInt(2 + 53 * Rnd), 3).Row

If NameRow = FamRow Then
MsgBox "Совпадение строк ! Не нужен Петр Петрович Алексей Алексеевич !"
Exit Sub
End If

Name = Sheets("Данные").Cells(NameRow, 2).Value
Fam = Sheets("Данные").Cells(FamRow, 3).Value
  
Range("C3").Value = Name & " " & Fam
 
Application.ScreenUpdating = True
End Sub

Sub ГенераторИО()
Dim Name As Variant, Fam As Variant
Dim Name1 As String, Fam1 As String
Randomize
Name = Application.Transpose(Sheets("Данные").Range("B2:B56"))
Fam = Application.Transpose(Sheets("Данные").Range("C2:C56"))
Name1 = Name(Int(Rnd() * 55))
Fam1 = Fam(Int(Rnd() * 55))
On Error Resume Next
Range("C3").Value = Name1 & " " & Fam1
'MsgBox "Генерация ИО прошла успешно !"
End Sub

Private Sub UserForm_Initialize()

Dim iLastRow As Long, k As Long
Dim myArray()

    With Worksheets("Данные")
        iLastRow = .Cells(.Rows.Count, 3).End(xlUp).Row 'последняя строка в столбец С
        myArray() = .Range("C2:C" & iLastRow).Value
    End With

    For k = LBound(myArray) To UBound(myArray)
        If myArray(k, 1) <> "" Then ListBox1.AddItem myArray(k, 1)
    Next k

End Sub