Help, I'm stuck! :ack

I can't decide what to call my last "chapter" in my book. Because the format of this book is different, I can't really call it a "chapter." And it's more like an "epilogue" but because it is nonfiction, I have to call it something else.

It's basically supplemental material.

I checked and came up with a list of names I like:

Appendage (sounds like anatony-related)
Notes (isn't this normally reserved for bibliographies?)
Postscript (liking this one)

What do you guys think? Is there a word I've forgotten?

Any advice would be greatly appreciated. THANKS!