Fantasycraft has a pretty good system for it. It breaks the standard weapons first into a group (edged, blunt, bow, thrown, black powder, siege and unarmed). You get a number of Proficiencies based on your Class (you also gain more as you level) that you can spend on one of the above groups. 1 proficiency lets you avoid untrained penalties for all normal weapons in the group, and 2 is called a Forte, gives you +1 to attacks using any weapon in the group, lets you also use exotic weapons in the group, and lets you take weapon feats.
Within each group, there are classifications of weapons, for example, Edged has Swords, Axes, Fencing Blades, Knives, Greatswords, Polearms, and Spears (I may be missing some).
Each of these types has multiple wraps within it, and each of these types has a 3-deep feat tree that give unique abilities that cause different weapons to actually have different "styles". Sword is full-on damage, Greatsword is area control, Axe focuses on brutal rending hits and damaging objects, knife is sneaky and utility, Fencing blade is focused on controlling your adjacent squares and punishing enemy mistakes, etc.
Within each type, every weapon is unique, they vary in terms of damage, critical range, Armor Piercing, and special qualities. For Instance, in knives, you have the Stilleto with a measly d4 damage, but AP 8 (most armor gives 1-3 DR, unless it's heavy stuff), then you have a main gauche which gives +1 Defence (AC), a Dagger with d6 damage, which can be thrown with no penalty, and a Kukri which has a higher chance of causing critical injuries, along others.
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