I'll try to help:
Peg Box: This skill goes up to level 3 and only toddlers can have this skill. When the toddler ages into child, they will start their logic skill level at the same level as this skill has achieved.
Xylophone: This skill goes up to level 3 and only toddlers can have this skill. When they age into Teens, they will start their Guitar skill level same as this skill level acquired. If the Late Night expansion pack is installed, then the Bass, Piano, and Drum skills will also be raised.
Collecting: The skill goes up to level 10. Sims will get a better chance when capturing a bug or insect and finding a gem or rock.
Mooch: A Sim with the Mooch trait can just mooch off of his or her neighbors. This skill goes up to a level of 10. Sims with the Mooch Trait can beg for money and food from Sims around them. The higher the Sim's Mooching skill, the more likely they will be able to mooch large quantities of money. It is harder to mooch from Sims with the Frugal trait.
Consignment (Ambitions): The skill goes up to level 10. As Sims sell objects in the consignment store their consignment skill also increases, allowing them to sell objects for great returns.
Child Cooking: Only child can get this skill. This skill goes up to level 3 and when the child aged into teen, they will start their Cooking skill level same as this skill level acquired.
Child Athletic (Generations): The Athletic skill is not available again for child sim since generations, this skill is replaced by a Child Athletic secret skill that earned when they working out. This skill goes up to level 3 and when the child aged into teen, they will start their Athletic level same as this skill level accuired.
Child Guitar (Generations): Only child can get this skill, This skill goes up to level 3 and when the child aged into teen, they will start their Guitar skill level same as this skill level acquired.
Child Bass (Generations + Late Night): Only child can get this skill. This skill goes up to level 3 and when the child aged into teen, they will start their Bass skill level same as this skill level acquired.
Child Drum (Generations + Late Night): Only child can get this skill. This skill goes up to level 3 and when the child aged into teen, they will start their Drum skill level same as this skill level acquired.
Child Piano (Generations + Late Night): Only child can get this skill. This skill goes up to level 3 and when the child aged into teen, they will start their Piano skill level same as this skill level acquired.
You need to add
Club Dancing (3 levels) and
Wildlife (6 levels) too.
I've seen another hidden skill called "
Band" or "
Rock Band", but I don't know how it works. It's only 1 level:
<SkillName>RockBand</SkillName>
<SkillDescription>RockBandDescription</SkillDescription>
<Hex>RockBand</Hex>
<CodeVersion>EP3</CodeVersion>
<CustomClassName>Sims3.Gameplay.Skills.RockBand,Sims3GameplaySystems</CustomClassName>
<MaxSkillLevel>1</MaxSkillLevel>
<Hidden>True</Hidden>
<Level_1>1</Level_1>
<AvailableAgeSpecies>Y,A,E</AvailableAgeSpecies>
<DreamsAndPromisesIcon>hud_band_skill_s</DreamsAndPromisesIcon>
<IconKey>hud_band_skill_s</IconKey>
<SkillUIIcon>skillobjectband</SkillUIIcon>
<kVenuesPlayedForLifetimeOpp value="10" />
<kMoneyMadeForLifetimeOpp value="25000" />
<kTipMultiplierForStar value="1.5" />
And you can see a hidden skill called "
Rubble Clearing" in the wikia, but I think is not in the game.
