D&D General What would your "fourth core rulebook" be?

[Minigiant]

Players Handbook- Book for Players
Dungeon Master's Guide- Book for DMs
Monster Manual- Book of Monsters
Tome of Magic- Both for rare Spells, Magic items, and Monsters

 

[Bomberooski]

A book along the lines of 3e's Unearthed Arcana, with lots of variant rules options and ways to customize the game for different playstyles.

I do think this would be cool. And would love to see it promoted and announced as being released in around 2 years so the game has some time to breath and creators/players have time to learn what is and isn’t working.

 

[DavyGreenwind]

A book of subsystems, such as naval combat, vehicles, mass warfare, exploration, crafting, harvesting, side businesses, lycanthropy, vampirism--systems not covered in the core rules, but seem to be common fodder for 3rd parties.

I'd call it "The Character's Worldbook" or something like that

 

[Vael]

Tbh, a lot of the suggestions I've seen look best within the DMG, so my suggestion is to move the the magic items into their own book and use all that space within the DMG for optional rules, campaign and adventure building.

 

[DEFCON 1]

To me the most logical book that could/would become a "fourth core" book would be the Manual of the Planes.

It's the one book that has universal application and has been published over and over regardless of edition, meaning that it already has a place in the ubiquity of D&D tomes. So take out the 40 pages of cosmology from the DMG, add in additional cosmological format, ideas, and details (including the Great Wheel, World Tree, Dawn War, Orrery), info on creating your own cosmology, then really delve into all the Inner and Outer Planes and places / reasons to adventure in them.

Its universality over the entire breadth of D&D and its editions make it the most logical in becoming core in my opinion.

 

[ART!]

Manual of Planes, with gods and such in the mix.

 

[Minigiant]

Tbh, a lot of the suggestions I've seen look best within the DMG, so my suggestion is to move the the magic items into their own book and use all that space within the DMG for optional rules, campaign and adventure building.

My suggestion was to only put the most iconic spells in the PHB and the most iconic magic items in the DMG.

Then put all the niche spells and items in its own book.

 

[Muso]

The Manual of the Planes

 

[AmerginLiath]

Like others, I would suggest Manual of the Planes as a “fourth core.” With the “D&D Multiverse” becoming more and more part of the default assumption, we see how much of the DMG in recent versions is devoted to describing the planes. A core MotP could be used for that material and much of what we see in a Deities and Demigods book. It could also perhaps have additional “example Material Plane” (campaign setting) material and present various Archdevil/Demon Lord/major planar figures not found in the MM. in doing so, that frees up space in the DMG for more material on things like monster design and Arms & Equipment discussion.

 

[Remathilis]

Depends on the Edition

1e: Unearthed Arcana
2e: Tome of Magic
3e: Psionics Handbook
4e: Adventurer's Vault
5e: Xanathar's Guide to Everything