There is some unfortunate disappointment with the new D&D Monster Manual. WotC probably panicked when they saw Matt Colville’s Flee Mortals and rethought everything they’d been working on. The alphabetization in particular is one area that annoys. It’s perhaps a clunky result of throwing the taxonomy up in the air when trying to rewrite everything.

What Should It Look Like?

There should be a really clean taxonomy of creature, type, category, and family.

• Creatures of a given type should be grouped into one entry.
• Those of a category should be grouped together in their own section.
• Those of a family should be merely identified in their stat block as belonging to that family.

Examples

• So a gelatinous cube should have its own entry but is identified as being a part of the family of “amorphs” or whatever. This would include the various oozes, slimes, and jellies, and the whole family would be immune to precision damage and resistant to bludgeoning damage (since they have no bones). Theoretically, you could have “gray ooze” and, say, “black ooze” in the same entry with slightly different stats and powers.
• The “red dragon” should be one entry with notes for what powers it gets as it ages. That entry should be grouped with other the dragons under a “Dragon” section. And all dragons should be in the “dragonkin” family along with pseudodragons, dragon turtles, wyverns, and sea serpents.
• Likewise, the “storm giant” and “frost giant” are their own entries grouped under a section on “Giants”. But ogres are under O and merely identified as belonging to the “giantkin” family.
• Creatures can be in no family (which is to say a family of their own) or in multiple families. A dracolich should be in both the “undead” family and “dragonkin” family.
• The common ghoul and lacedon/water ghoul should be together in a single “ghoul” entry. They should be in the “undead” family with ghosts, wraiths, wights, and vampires. But there’s no need to try to group all undead together into their own section.
• “Demon” and “devil” would be separate sections, and all such creatures would be identified in their stat blocks as part of the “fiend” family.
• The “beast” family can include any ordinary animal or its giant version. These can probably be grouped, so that “wolf” and “giant wolf” are in one stat block, as are “eagle” and “giant eagle”.
• Similarly, various goblins (warrior, guard, shaman, chieftain) can probably be gathered into one entry. This would be part of the “humanoid” family, altho goblins and hobgoblins would be noted in their descriptions as being closely related. There’s no need to group them into a “goblinoid” category, tho.
• Other categories could include “dinosaur” as well as “lycanthrope” and “elemental”. Other families could include “fae” and perhaps “plant” and “construct”.

With this kind of taxonomy, you can say that clerics can turn undead, which means any creature in the “undead” family. Or you can say a weapon is “+2 vs fiends [family]”, regardless of whether they’re demons or devils, or “+2 vs giantkin [category]”.

Abilities

Creature abilities should be geared toward enhancing the drama and challenge of an adventure, including things like being able to summon minions and flee via some magical or mundane escape route.

Hooks

Each creature needs a list of hooks to help GMs figure out how to use them. What sort of goal might such a creature have that would put it in conflict with civilized folk and provoke adventurers to hunt it? Preying on livestock, wrecking fields, fouling woodlands, etc., and of course amassing treasure….

Lairs

There should be a lot of maps in a monster book. GMs need to know what the creatures’ lairs look like, so they should be listed for each creature and mapped. Of course, a ruined temple might just as easily be the lair of a lich as a band of goblins, so the map would often only be generally keyed (“great hall”, etc.), not keyed for any specific monster.