Modular Weapons
Modular Weapons is a replacement for the weapons found in the Player's Handbook. Instead of listing a large number of specific weapons, it provides a framework to quickly create stats for any weapon you please. It is designed to make it very difficult to create a weapon that it useless or strictly inferior to another option, while also giving each weapon a unique feel.
To create a weapon with this sytem, start with a simple melee weapon that deals 1d6 damage. Then, choose an archetype for your weapon: axe, bludgeon, bow, crossbow, polearm, sword, or thrown weapon, all detailed below. A weapon gains special abilities based on its archetype. Finally, you can choose to apply any number of properties to your weapon.
Wielding a melee weapon or crossbow in two hands increases the damage die by 1 step.
Archetypes
Axes deal slashing damage, and excel at cutting through large swaths of weak enemies. When you miss a creature with an axe, you can use your reaction to make a melee weapon attack with disadvantage against another creature within range.
Bludgeons (which include clubs, maces, warhammers, mauls and similar) deal bludgeoning damage and are unequaled in the sheer force they can bring to bear. When you shove a creature while wielding a bludgeon, you deal bludgeoning damage equal to your Strength modifier. If the bludgeon is wielded in two hands, you have advantage on shove attempts.
Bows deal piercing damage and have unrivaled accuracy at long distances. All bows are two-handed ranged weapons. Simple bows have a range of (120/480), while martial bows have a range of (150/600).
Crossbows deal piercing damage and are deadly at close range. All crossbows are ranged weapons. Simple crossbows have a range of (80/320), while martial crossbows have a range of (100/400).
Polearms (which include spears, tridents, halberds, glaives and similar) deal piercing or slashing damage and are the preferred weapon of cautious warriors who try to keep their enemy at a safe distance. You add 5 feet to your reach when you attack with a polearm, or 10 feet if the polearm is wielded with two hands.
Swords (which include daggers, sabers, estocs, rapiers and similar) deal piercing or slashing damage and are known for inflicting debilitating injuries. Swords score a critical hit on a 19 or 20. This ability stacks with other abilities that increase your critical threat range. If the sword is wielded in two hands, you multiply your relevant ability modifier by two on a critical hit, in addition to the damage dice.
Thrown Weapons (which include javelins, throwing axes, and similar) are aerodynamic and heavier than normal projectiles. They can be thrown with a range of (30/120), and a creature hit by one or more thrown weapons is staggered, reducing their movement speed by 10 until the end of their next turn.
Properties
Martial. A martial weapon's damage die is increased by 1 step, but it requires martial weapon proficiency.
Finesse. When making an attack with a melee finesse weapon, you can use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls. The weapon's damage die is decreased by 1 step.
Light. A light weapon is small and easy to handle, making it ideal for use when fighting with two weapons. Additionally, a melee light weapon can be thrown with a range of (20/60). The weapon's damage die is decreased by 1 step unless it has the Finesse property.
Heavy. Small creatures have disadvantage on attack rolls with heavy weapons, but certain features such as the Great Weapon Master feat might give them special benefits.
Specific Weapon Proficiencies
Some classes, like the bard, offer proficiency in only a few specific martial weapons. To make sense of these proficiencies with Modular Weapons, you can recreate the core weapons using this system. For example, a hand crossbow is a Martial crossbow with Light, a shortsword is a Martial sword with Light and Finesse, and a longsword is a Martial sword.
Extensions
DMs who would like to emphasize unarmed combat in their settings without requiring every player play a monk can add an additional weapon archetype: Unarmed Strikes. Unarmed strikes are basic melee attacks, and like all weapons, they can be modified with the Martial, Finesse, Light, or Heavy properties. Light Unarmed Strikes cannot be thrown (although they remain well-suited for two-weapon fighting).
Since unarmed strikes aren't external objects, different weapon properties represent different styles of martial arts and levels of training. A martial, finesse, and light unarmed strike might represent a complicated fighting style based on quick movement and rapid, low-impact strikes. A simple, heavy unarmed strike might represent the ungainly, brutish fighting style of a local strongman. For simplicity, each character should choose their own favored fighting style to use for their unarmed strikes.
Unlike other weapons, unarmed strikes offer no particular bonus in combat. Instead, their strength lies in the fact that they cost no money and are always available, even when circumstance would normally make using weapons impossible.
At the DMs discretion, proficiency with Unarmed Strikes can either replace proficiency in other weapons, or else be automatically granted to any character who is proficient in simple or martial weapons.