TTRPG Foes - Stats, Lore, Design

Design

Monster stat blocks are too complicated! You only need to know three numbers: HP, Defense (or AC), and Damage. That's it! Maybe some notes about something special about it or the way it acts. Reader, you might be asking "what about this or that stat?" Sure. A to-hit bonus for example. Let me then rephrase my previous statement. You only need three numbers to describe an individual statistic.

I'm going to give you a game design tip from classic D&D. In classic D&D, every monster's stats were based on their number of hit dice. A monster with 3 hit dice had a +3 to hit and had the same saving throws as a level 3 fighter. That's very slick. It gets better! Monsters tended to appear with other monsters with the same number of hit dice. In fact, a dungeon would be several floors deep and the monster's number of hit die tended to match the floor number! Therefore, the saving throws and to-hit bonuses could easily be written on the map! What does that describe? A global statistic; in other words, a number representing the average statistic of an NPC in an area, room, or scene with a set difficulty.

So, consider treating each enemy as having individual stats like HP and what kind of damage it does, and treat each enemy has global stats that are dependent on the difficulty that the game's designer (the GM) set for the room. This simplifies prepping and running the game! Imagine determining that all the monsters in the room have a +4 to hit? Why should it vary? Really, what difference does a +1 or +2 make?

This is a supplement to a 2d6 game I wrote about here. Note that NPCs are not designed with the same logic as a PC! Here is a breakdown of statistics to use for NPCs:

• Hit Points (HP): How much points of damage an NPC can take. NPCs typically die at 0 HP. The game assumes generally low hit point values.
• HP values given are average for that variety of NPC.
• Small, weak enemies (ex: goblins) typically have 2-3 HP. They typically die in one hit.
• Human combatants typically have 5 HP and can typically survive one hit.
• Many enemies have 10 or so HP to reflect that they are comparable to a PC.
• Enemies that are larger than humans, lions, bears, or ogres, have 15+ HP.
• Giants and dragon tend to have 20 to 30 or more HP.
• Defense (Def): How hard the monster is to hit.
• 9 is the basic number a player needs to roll to succeed in the 2d6 game; however, individual monsters can have their own defense.
• Defense could easily be tied to the global difficulty.
• Damage (Dmg): It's attacks (claw, bite or weapon for example) and the number of damage dice it rolls for all of its attacks!
• Often, the damage will be based on the weapon it swings or its size class! A human-sized monster will do damage comparable to humans, a monster that is double the size of a human, like a lion, bear, or ogre, will do 2d6. Giants and dragons can be assumed to do 3d6.
• When "by weapon" is given for damage, this means you refer to typical weapon damage and even typical barehanded damage. 
• To-Hit Bonus (Hit): The bonus added to a monster's 2d6 toll to hit.
• This number is typically not written and is left up to the global difficulty.
• Damage Reduction (DR): This number is subtracted from damage received representing the amount of protection provided by the armor worn by the NPC, or sometimes a natural armor provided by a natural armor or armored body.
• If this number is not given, treat as 0. Most NPCs are considered unarmored and so they reasonably have a 0 DR.
• 1 DR is comparable to light armor.
• 3 DR is comparable to heavy or metal armor.
• Saving Throw (Save): Some attacks force a PC or NPC to make a roll to reduce the harm or to avoid some effect. The save represents how well a character is able to successfully avoid or resist an attack.
• This number is typically not given and is left up to the global difficulty.
• Classically there are different kinds of saves for different kinds of attacks. They usually break down to dodging an effect that can be dodged, or to resist an attack that cannot be dodged with either physical toughness or mental resilience.
• An NPC can be considered good or poor at a particular save as it suits them. A flying enemy may be considered good at dodging while airborne, etc. A warrior may be good at resisting fatigue. A wizard may be good at resisting mind control. Use your judgement. If an NPC is considered poor at a particular save, simply do not let them use the Save bonus offered by the global difficulty!
• Movement (Move): How far a character can move per turn. If move is not given, assume the typical movement for this NPC.
• If using grid and mini play, Move is typically six inches or one pencil length.
• If using theater of the mind, assume approximately 30 ft as typical.
• If using zones, one zone is typical.
• For simplicity, consider there are only three speeds: Slow (half a pencil length), normal (one pencil length), and fast (one and a half pencil lengths). If any move penalties are applied, assume that the character's move is lessened by one (ex: from fast to normal or normal to slow).

MONSTERS LIST

I believe that your monster list ought to be curated meaning you don't include everything! Your setting is not a kitchen sink. Below I have provided a curated list of stat blocks that might be found in a low fantasy setting. Some of the more fantastic things would occur rarely.

Alligator / Crocodile

HP 10 Def 9 Bite 1d6+2 DR 1

If bitten, you are automatically grappled

If grappled, the alligator can deathroll for 2d6 damage

Alligator / Crocodile, Giant

HP 18 Def 9 Bite 2d6+2 DR 3

If bitten, you are automatically grappled

If grappled, the alligator can deathroll for 2d6 damage

Bear (Grizzly or otherwise)

HP 18 Def 9 Bite or Claws 2d

Beastman (aka Hnoll, spotted, furry body resembles a man, head like a hyena)

HP 12 Def 10 Dmg by weapon or 1d6 bite

Blood Frenzy: Beastmen prioritize bloodied opponents

Bogyman (AKA Troll)

HP 15 Def 9 Dmg based on weapon

Regeneration: If slain, recovers in 24 hours with +1 to max HP and damage unless burned and beheaded.

Bugaboo (AKA Goblin)

HP 2-3 Def 9 Dmg based on weapon

Bullman (AKA Minotaur)

HP 20 Def 9 Hoof, Horns or Weapon 2d6

Gore - If gored, make a brawling check to avoid being grappled

Chimera (AKA Amalgam)

HP 25 Def 10 Claw, bite, Ram, etc. 2d6

Fire breath (15' Stream) 2d6

Tail can bite and inflict poison

(The) Damned (AKA)

HP 10 Def 9 Dmg by weapon

Weak to silver and magic

Deerman

HP 20 Def 9 Hoof, Atlers, or Weapon 2d6

Doll (AKA Golem)

HP 12 Def 9 Dmg based on weapon

*Immune to charm, sleep, paralysis, poison

Cannot fail morale checks

Dragon

HP 30 Def 13+ Claw, bite, etc. 3d6 DR 3

Fire breath (either 15' cone or 25' line) 3d6

PCs save vs fear or difficulty +1

Eaterman Bush

HP 10 Def 9 Dmg 1d6-1 (minimum 1)

Elemental, Major (Earth, Water, Air, or Fire)

HP 15 Def 9 Dmg 1d6+1

Not harmed by mundane weapons

Elemental, Minor (Earth, Water, Air, or Fire)

HP 8 Def 9 Dmg 1d6-1 (minimum 1)

Not harmed by mundane weapons

Elf

HP 10 Def 10 Dmg by weapon

Magical Bloodline: Bonus to Saves vs Magic

Affinity to Woods: Bonus to track and hide in forests

Fiend, Major (AKA demon or devil)

HP 15 Def 9 Dmg 1d6+1

Not harmed by mundane weapons

Fiend, Minor (AKA demon or devil)

HP 8 Def 9 Dmg 1d6-1 (minimum 1)

Not harmed by mundane weapons

Ghost

HP 10 Def 9* Touch 1d6 (max HP)

Life drain: damage is applied to max HP

Not harmed by mundane weapons

Levitates

Intangible

Griffon

HP 20 Def 10 Dmg 2d6

Flies

Big and strong enough to carry a human

Hangman's Tree

HP 30 Def 9 Strike 2d6 DR 1

Strike with branches and throw or pin, or ensnare to grapple!

Homunculus (Plural Homunculi, AKA artificial human, a product of alchemy)

HP 5 Def 9 Strike 1d6

Defect: The creation process is too precise. No two homunculi come out the same. All have a defect; if not physical, then mental.

Hybrid (any non-typical creature with features of two or more creatures, typically a product of alchemy)

HP 10 Def 9 Dmg by weapon

Leech (AKA Vampire)

HP 20 Def 10 Dmg 2d6 DR by armor

Liger

HP 30 Def 9 Bite 2d6

Makes charge attacks - jaws first and pins the target.

Lizardman

HP 5 Def 9 Dmg by weapon 1d6-1 (min 1)

Vulnerable to cold

Manticore

HP 20 Def 9 Claw or Tail 2d6

Tail has a 10 ft reach

Spike 30'

Nymph (Including siren, dryad, Ice Maiden, Venus)

HP 5 Def 9 By weapon

Charming Appearance (nymph): Upon sight, men save vs charm

Charming Gaze (dryads) or Song (sirens): when in seeing or hearing range, save vs mind control

Ogre

HP 18 Def 9 Dmg 1d6+2

+4 to Brawling

If hit, save vs being knocked prone!

Ratdog (a rat-doberman mix)

HP 8 Def 9 Bite 1d6-1 (min 1), Save vs Disease

If bitten, Ratdog can choose to grapple with its jaws

Ratkin (creatures resembling rat men about two feet tall)

HP 2-3 Def 9 Bite 1d3 + Save vs Disease

Reaper (reaper is a class; each reaper is an individual fulling the role of a reaper uniquely)

HP 20 Def 10 Dmg by Weapon

Green Flame: Cast a projectile of green flame (1d6); if hit, you are ignited

Eerie Lantern: When lit, this light stuns the living with fear. Roll to save.

Dirge: Sings a song that quells hostile undead

Passage: Create a passage to the afterlife.

Revenant

HP 10 Def 9 Dmg based on weapon

Undead, but retains their personality although twisted with a need for vengeance

Immune to charm, paralysis, sleep, poison

Does not heal

Cannot fail morale checks

Scare Crow (enchanted object)

HP 5 Def 8 Dmg 1d3

Call Swarm (of crows) up to 3 swarms. Swarm has 10 HP, Def 9, and does 1d6 damage

Command Swarm (of crows) attack for 1d6 damage

Skeleton

HP 5 Def 8 Dmg 1d6 Move Slow

Slime (a product of alchemy, rarely occurring in nature)

HP 5 Def 8 Dmg 1d6

Acidic; -1 to equipment on contact

Not harmed by mundane attacks

Snake Bearer (AKA Ophiuchus) 

HP 5 Def 9 Dmg by weapon

Its left arm ends with the head of a venomous snake! On a hit, save vs Poison.

Snakeman

HP 5 Def 10 Dmg by weapon

Its left arm ends with the head of a venomous snake! On a hit, save vs Poison.

Snatcher (AKA Harpy)

HP 8 Def 10 Dmg 1d6

Flight, fast speed

Spider, Giant (a 3ft tall spider)

HP 10 Def 9 Dmg 1d6-1, min 1, save vs Poison

Web, save vs Grappled!

Titan Snake (Aka Goliath)

HP 40 Def 9 Bite or Constrict 3d6

Snake (ex: Viper)

HP 2-3 Def 9    Bite save vs deadly poison

Wil-o-wisp

HP 2-3 Def 9    Dmg none

Not harmed by mundane attacks

Flies and sheds light like a torch

Hypnosis upon sight: Save or follow it, possibly until you die of starvation

Witch (AKA Hag, Crone)

HP 10 Def 9 Damage by spell

Sleep (AOW up to three within 15 ft)

Deep Mist: Creates an area of concealing, chilly fog. To-hit -2!

Poisonous Touch vs 1 within 5 ft. Save vs poison.

Curse Word vs 1 within 30 ft, save vs disease, mute, or blindness

Illusionary Foe within 60 ft: Conjure an illusionary foe to district and chase one PC.

Conjure Demon or Elemental within 20 ft.

Enchant Object: Create an NPC such as a scare crow from one large object or many smaller objects

Petrifying Spit (10 ft) vs 1: Save or become stone!

Either Fly or Port - a witch can fly for the duration of the encounter, or teleport as a movement for the duration of the encounter. Her normal movement is doubled.

Frost Bolt (1d6): Cast a ray of chilly air and ice at one Character! On a hit, the creature's move is reduced to half their normal move.

Scry: Remotely view a scene in a reflective object, usually a crystal ball or the surface of water.

Create Zombie or Golem (requires one workday): The witch can create a revenant or zombie from a corpse, neither of which is obedient, or a golem from a mixture of human ashes mixed with clay. 

Werewolf

HP 10 Def 10 Claw or Bite 1d6

On a hit, save vs curse of the werewolf (lycanthropy)

Requires silver weapons or magic to harm.

Wolf

HP 5 Def 10 Bite 1d6-1 (min 1)

If bitten, wolf can choose to grapple

Zombie

HP 10 Def 9 Dmg based on weapon Move Slow

Grapples first, then bites

Immune to charm, paralysis, sleep, poison

Rots and stinks

Cannot fail morale checks