The Kuo-Toa section in MMV has some neat toys. Two of them are restricted to Kuo-Toa, though.
The Kuo-Toan Harpoon, an exotic one-handed¹ throwing weapon that deals 1d10/x2 Piercing damage and has a range increment of 30ft. That's already pretty good - but it gets better.
A) Each time the harpoon damages a creature, they have to make a Reflex save vs. 10 + [Damage Dealt], or else they get harpooned.
B) Harpooned creatures halve their speed, can't charge or run, and has to make a DC 15 Concentration check to cast spells.
C) Pulling out the harpoon takes a full-round action and two free hands - it deals 1d10 damage unless you make a DC 15 Heal check.
D) The wielder can hold onto the attached chain, preventing a harpooned creature from moving more than 30ft away unless they win an opposed Strength check.
E) They can wrap it around a shield they've used the Adhesive ability on as a Swift action to gain a +5 bonus on all such Strength checks.
F) After wrapping it around a shield, they can slam it into the ground as a Standard action, which turns the opposed Strength check to move away into a DC 20 Strength check.
By RAW, D, E, and F can only be used by one monster (the Kuo-Toa Harpooner), but I think any reasonable DM would let you use D even if you weren't a Kuo-Toa (E and F do require a particular racial trait, so you're out of luck there.)
Oh, and the fact that removing the harpoon deals damage to you means that pulling a harpoon out of you doesn't always work.
¹ OK, by RAW it isn't any of the three - I'm picking this up from a statblock here.
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The Kuo-Toa Monasticism and Mind-Shattering Strike are interesting feats for Kuo-Toa Monks.
a) Kuo-Toa Monasticism is a... bit poorly written (it doesn't have a duration), but the important benefit is that you can take a Swift action to make one of your extra attacks from Flurry of Blows automatically hit if your first attack hit.
b) Mind-Shattering Strike gives you an extra usage of Stunning Blow. More importantly, it lets you spend a Stunning Blow usage to make the creature you hit with an unarmed attack attack the nearest non-Kuo-Toa unless they make a Will save vs. 10+1/2 HD+Wis.
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Yep, all of them are poorly written, but they're fun nonetheless.