Unsure how far to go.
If you want to make your campaign really interesting, how far can you go in making new monsters, artifacts, and such?
Essentially, should you be able to create entire new subtypes of monsters, such as, for example, adding a Spectral Subtype to the Undead Type? Create new deities? Boss monsters who are Legendary but nobody has ever heard of? And should you be able to create new weapons with completely new traits? This is my first time creating one and I'm not quite sure how crazy I can go with it.