Not sure there is an alternative part number list. But they are all inter-compatible. What you want to do is use the latest compatible transformer with your Mac. I believe the latest compatible transformer for the 128K is the SE/30. The Classic may work, but if so there is a CRT compatibility issue with some of them. Since the exact part number is not likely available any longer, an equivalent part would be desirable ... again assuming you can find it. Sadly it's not as easy as it used to be, even 5 years ago ...

I believe JDW has an excellent spreadsheet for the compact Mac replacement components, but can't remember if it includes the transformer ...