[SixOfSpades]

All launchers are not created equal. First let's go into the question of damage: A plain Short Bow grants -0 to THAC0 and +0 to damage. A Shortbow+1 grants -1 to THAC0 and +0 to damage. A Shortbow+2 grants -2 to THAC0 and +0 to damage. A Shortbow+3 grants -3 to THAC0 and +0 to damage. Seeing a pattern here? Shortbows do not add damage corresponding with their weapon enchantment. Neither do Longbows. (They do, however, all have an innate +1 to ApR, so that's fair, I suppose.) The only Bows that grant Damage bonuses are the Tugian Bow and all Composite Longbows (which add +1), the Ripper+2 (which adds +2), and the Strongarm+2 (which adds +3).
Slings and Crossbows, however, do add damage with their enchantment: A Light Crossbow+1 adds +1 bonuses to THAC0 and damage, a Light Crossbow+3 adds +3 bonuses to THAC0 and damage.

Not all ammunition is created equal, either: Magical Arrows and Bolts do not add damage corresponding with their weapon enchantment--Bullets do. A mundane Bullet does 1D4+1 damage, a Bullet+3 does 1D4+4.
There is also the cheesy exploit of abusing the fact that ALL Slings, not just the Sling of Seeking, add the user's Strength modifier to the damage of the weapon, provided the Bullets in use are of at least +1 enchantment.

If what I just said has you sold as far as Slings are concerned, consider that for some reason, Sahuagin and Kou-Toa really really know how to make Bolts be a lot more damaging than anyone else. Regular Bolts do 1D8 damage. Paralytic Bolts, however, do 1D10 (the same as a Two-Handed Sword), and Kou-Toa a whopping 2D6. And that's not counting their very nice additional enchantments, too.

In addition to Arrows of Biting and Dispelling, the Fletcher (Perter) in Waukeen's Promenade also stocks a large number of Arrows of Detonation. Although I do have some mods installed, so that might not be in the original game.