Polyhedron magazines featured many monsters across it's many issues, and they were all included in the (technically "unofficial") book "The Lost Adventures Volume III".
Most of the monsters list their creators, which must be included in the monster pages.
There are some existing monsters, like the Skum, that were first published in this book.
TSR 202X - The Lost Adventures Volume III
Polyhedron magazines featured many monsters across it's many issues, and they were all included in the (technically "unofficial") book "The Lost Adventures Volume III".
Most of the monsters list their creators, which must be included in the monster pages.
There are some existing monsters, like the Skum, that were first published in this book.