Create different weapon tiers, each one stronger than the last.
eg. Common < Uncommon < Rare < Legendary < Godly

Have different weapon types.
eg. Dagger, Sword, Axe, Bludgeon, Claw, Pickaxe, Polearm, Spear, Unarmed, Whip, Bow, Crossbow, Gun, Thrown.

And since it's a TTRPG, make each weapon unique with different flavour texts and attributes(enemies can have generic one just for easier loot-selling, unless it's a boss).
eg. Rare Redvenom Blade, made from a mixture of poisonous blood and demon blood, deals 1d4+4 damage and grants a +4 agility bonus.