The problem I encountered was that in making their racial package, I wanted to give them a froggy tongue for grappling. Most of the elements of that made sense to me: Extra Arms with Temporary Disadvantage (Mute), Extra-Flexible, and Long. The problem I came across is that Long is just too expensive as an enhancement when it's applied to a limb that can't grasp a weapon (that probably applies to Extra Legs, too, now that I think of it.) It's +100% for each level, and for a frog tongue at SM 0 you need at least two levels, making the final cost for a grappling tongue 33 points. That's a bit much.
I can always just handwave costs, but I usually prefer a more methodical approach. It occurred to me that it didn't count as a fine manipulator, so I applied the limitation for that. I also decided that NFM should reduce the cost for the Long enhancement, halving its value. It's just not as useful when you can't use the limb to handle weapons. That made the cost a more reasonable 21 points, which is still above my own gut reaction of its being worth about 10 points, but I can live with it.
One of the things I like about GURPS is that there doesn't even have to be an absolutely correct way to approach this issue or any related costs. There might be a half-dozen people ready to say that advantage should be 33 points, or others who say it shouldn't even be 10, and there's nothing wrong with that provided you're prepared to do it my way when I'm running.
Here's what I came up with, if you're interested in the work in progress. I still need to figure out how to model the whole drying out thing (Dependency seems obvious), though I may not use that, as well as trying to get a ballpark for how long they can stay underwater. I know some frogs breathe through their skin but I don't know if they all do. Sadly, our GURPS community buddy Pizard has never done frogs so I'm on my own on this one.
Frog-men (27 points so far)
Attributes: DX +1 , IQ -1 [-20].
Secondary Characteristic Modifiers: Per +1 , Will +1 . SM 0.
Advantages: Amphibious , Extra Arms 1 (Tongue; Extra-Flexible +50%, Long 2 +100%, Not a Fine Manipulator -40%, Switchable +10%, Temporary Disadvantage (Cannot Speak) -15%) , Super Jump 1 .
Disadvantages: Appearance (Unattractive) [-4], Bully (12) [-10], Callous (Not towards other Bullywugs, -20%) [-4], Social Stigma (Barbarian) [-10]. I'm not sure if the Social Stigma shouldn't be upgraded to Monster.
AD&D 1st Edition Fiend Folio
AD&D 2nd Edition Complete Book of Humanoids