For i = 1 to 10

with textbox <= сюда нужно подставить значение переменной i
 ...
 ...
 ...
end with

next i

with textbox & i
with textbox + i

Dim arrayOsnova As Variant
    arrayOsnova = Array()
Dim arrayDop As Variant
Dim k As Long
For k = 1 To 3
    arrayDop = Range(Cells(1, k), Cells(4, k))
    ReDim Preserve arrayOsnova(k)
    arrayOsnova(k) = arrayDop
Next k

Dim colOsnova As New Collection
    Set colOsnova = New Collection
Dim arrayDop, arrayDop2 As Variant

arrayDop = Range("a1:a4")
arrayDop2 = Range("b1:b4")
colOsnova.Add (arrayDop)
colOsnova.Add (arrayDop2)

testValue = Application.InputBox("Введите число от 1 до 5")
    If testValue= False Then
        Exit Sub
    ElseIf testValue>= 1 And testValue<= 5 Then
        UserForm2.Show
    Else
        MsgBox "Введено неверное значение"
        Exit Sub
    End If