These tips are designed to fit some cheap and easily ordered pliers with replaceable tips

If you get the pliers at that link then these prints will provide you with replacement blank tips and a custom tip that contains channels for straightening a variety of small tube and wire diameters. That's the one I needed :)

You can make the tips of various materials if you need, for example, softer tips. The blank is also useful for whatever plier tip ideas you might have as you can build from it. I used ABS so I can also bond other shapes and things to the tips with acetone if desired.