This section offers a selection of common monster powers you can apply to any quick-build monster to give them a stronger mechanical flavor, make them more tactically interesting, or reinforce their behavior in the story of your game.
Any creature who moves within 10 feet of this creature or who starts their turn there takes CR damage of a type appropriate for this creature.
Reskin this aura to meet your needs based on the damage type. A fire elemental can radiate an aura of fire, while an undead might radiate necrotic damage. You can also describe this effect as a magical aura dealing force damage or a holy aura dealing radiant damage, or even have a many-armed creature wielding swords to create an aura of slashing damage.
This creature’s melee weapon attacks deal an extra CR damage of a type appropriate for the creature.
As with Damaging Aura, this trait can be customized for many types of creatures by choosing a thematic damage type. A warrior might wield a greatsword that deals extra fire or lightning damage as a boon bestowed by their god. A mini-boss undead could deal necrotic or cold damage to represent their innate supernatural power.
When attacking a target whose current hit points are below half their hit point maximum, this creature has Advantage on attack rolls and deals an extra CR damage when they hit.
This trait makes a monster extremely dangerous in a tough fight, and encourages the characters to use healing resources.
At the start of their turn, this creature can gain Advantage on all melee weapon attack rolls made during this turn, but attack rolls against them have Advantage until the start of their next turn.
In addition to providing a combat boost for a foe, this trait can help accelerate a fight that’s gone on long enough, by letting the characters hit the last remaining foes more often.
This creature has a +CR bonus to damage rolls, and scores a critical hit on an unmodified attack roll of 18–20.
This simple trait is a default you can use to increase the damage dealt by any monster.
When this creature hits a target with a ranged attack, allies of this creature who can see the target have Advantage on attack rolls against the target until the start of this creature’s next turn.
Let a monster apply pressure to a specific target with this power, especially if that target is wounded or in a vulnerable position. Make the foe’s action obvious, so that the players know to react to it and can help the targeted character survive the ensuing focused fire.
When this creature is reduced to 0 hit points, they drop Prone and are indistinguishable from a dead creature. At the start of their next turn, this creature stands up without using any movement and has 2 × CR hit points. They can then take their turn normally.
This trait can represent a clever combatant playing dead, a warrior with incredible resolve, or a creature such as an undead or an ooze who refuses to die.
At the start of this creature’s turn, they can attempt a saving throw against any effect on them that can be ended by a successful saving throw.
This power can protect vulnerable combatants and bosses from being shut down by spells. It can represent magical mastery, divine favor, luck, or a specific quality of the creature. As a variant, using this trait could require the foe to take 2 × CR damage if the new saving throw is successful, representing the exertion made to overcome the effect.
When this creature’s current hit points are below half their hit point maximum, the creature deals CR extra damage with each of their attacks.
This trait works best when given to a single important foe, and when you describe the monster’s refusal to surrender despite their many wounds. This lets the players know they can focus fire to finish the creature off, minimizing their damage potential.
This creature has Advantage on Dexterity (Stealth) checks.
Foes fighting in obscured areas or behind cover can benefit from this trait, which can represent natural camouflage or well-practiced skill.
Source: Lazy DM's Forge of Foes