List of Traits in The Sims 4

Growing Up reward traits:

Infant to Toddler reward trait: (All base game)

Top Notch Infant - trait_Reward_Infant_TopNotch
Happy Infant - trait_Reward_Infant_Happy
Unhappy Infant - trait_Reward_Infant_Unhappy

Toddler to Child reward trait: (All base game)

Top-Notch Toddler - trait_Top_Notch_Toddler
Happy Toddler - trait_Happy_Toddler

Infant Quirks: (All Growing Together)

Early Riser - trait_Human_Infant_Element_RisesWithTheSun
(Hidden) - trait_Hidden_Infant_Element_RisesWithTheSun
Feeding Tinkler - trait_Human_Infant_Element_PeesDuringFeeding
(Hidden) - trait_Hidden_Infant_Element_PeesDuringFeeding
Free-Air Tinkler - trait_Human_Infant_Element_PeesDuringChanges
(Hidden) - trait_Hidden_Infant_Element_PeesDuringChanges
Frequently Hiccups - trait_Human_Infant_Element_FrequentlyHiccups
(Hidden) - trait_Hidden_Infant_Element_FrequentlyHiccups
Frequently Sneezes - trait_Human_Infant_Element_FrequentlySneezes
(Hidden) - trait_Hidden_Infant_Element_FrequentlySneezes
Gassy - trait_Human_Infant_Element_Gassy
(Hidden) - trait_Hidden_Infant_Element_Gassy
Good Appetite - trait_Human_Infant_Element_GoodAppetite
(Hidden) - trait_Hidden_Infant_Element_GoodAppetite
Happy Spitter - trait_Human_Infant_Element_HappySpitter
(Hidden) - trait_Hidden_Infant_Element_HappySpitter
Hates Being Held - trait_Human_Infant_Element_HatesBeingHeld
(Hidden) - trait_Hidden_Infant_Element_HatesBeingHeld
Hates Wakeup Time - trait_Human_Infant_Element_HatesWakingUp
(Hidden) - trait_Hidden_Infant_Element_HatesWakingUp
Little Babbler - trait_Human_Infant_Element_Talker
(Hidden) - trait_Hidden_Infant_Element_Talker
Loves Being Held - trait_Human_Infant_Element_LovesBeingHeld
(Hidden) - trait_Hidden_Infant_Element_LovesBeingHeld
Loves Sounds - trait_Human_Infant_Element_ObsessedWithSound
(Hidden) - trait_Hidden_Infant_Element_ObsessedWithSound
Loves Wakeup Time - trait_Human_Infant_Element_LovesWakingUp
(Hidden) - trait_Hidden_Infant_Element_LovesWakingUp
Messy Eater - trait_Human_Infant_Element_MessyEater
(Hidden) - trait_Hidden_Infant_Element_MessyEater
Picky Eater - trait_Human_Infant_Element_PickyEater
(Hidden) - trait_Hidden_Infant_Element_PickyEater
Self-Soother - trait_Human_Infant_Element_SelfSoother
(Hidden) - trait_Hidden_Infant_Element_SelfSoother
Snuggly Sleeper - trait_Human_Infant_Element_OnlySleepsWhenHeld
(Hidden) - trait_Hidden_Infant_Element_OnlySleepsWhenHeld

These can be more easily assigned with testingcheats by shift-clicking on an infant and going to Pack Cheats.../Expansion Packs.../EP13 - Growing Together.../Infant Quirks... menu.

Toddler Quirks: (All Growing Together)

Aggressive - trait_Human_ToddlerPersonalityUpdate_Visible_Aggressive
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_Aggressive
Destructive - trait_Human_ToddlerPersonalityUpdate_Visible_Destructive
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_Destructive
Early Riser - trait_Human_ToddlerPersonalityUpdate_Visible_EarlyRiser
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_EarlyRiser
Good Appetite - trait_Human_ToddlerPersonalityUpdate_Visible_GoodAppetite
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_GoodAppetite
Hates Bedtime - trait_Human_ToddlerPersonalityUpdate_Visible_HatesBedtime
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_HatesBedtime
Hates Being Carried - trait_Human_ToddlerPersonalityUpdate_Visible_HatesCarry
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_HatesCarry
Hates Wakeup Time - trait_Human_ToddlerPersonalityUpdate_Visible_HatesWakeup
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_HatesWakeup
Heavy Sleeper - trait_Human_ToddlerPersonalityUpdate_Visible_HeavySleeper
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_HeavySleeper
Light Sleeper - trait_Human_ToddlerPersonalityUpdate_Visible_LightSleeper
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_LightSleeper
Little Singer - trait_Human_ToddlerPersonalityUpdate_Visible_Singer
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_Singer
Loves Being Carried - trait_Human_ToddlerPersonalityUpdate_Visible_LovesCarry
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_LovesCarry
Loves Books - trait_Human_ToddlerPersonalityUpdate_Visible_BookLover
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_BookLover
Loves Sounds - trait_Human_ToddlerPersonalityUpdate_Visible_AudioLover
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_AudioLover
Loves Wakeup Time - trait_Human_ToddlerPersonalityUpdate_Visible_LovesWakeup
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_LovesWakeup
Loves Water - trait_Human_ToddlerPersonalityUpdate_Visible_WaterLover
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_WaterLover
Messy Eater - trait_Human_ToddlerPersonalityUpdate_Visible_MessyEater
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_MessyEater
Picky Eater - trait_Human_ToddlerPersonalityUpdate_Visible_PickyEater
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_PickyEater
Wanderer - trait_Human_ToddlerPersonalityUpdate_Visible_RunsAway
(Hidden) - trait_Hidden_ToddlerPersonalityUpdate_RunsAway

These can be more easily assigned with testingcheats by shift-clicking on an infant and going to Pack Cheats.../Expansion Packs.../EP13 - Growing Together.../Toddler Quirks... menu.

Childhood Confidence Trait & Reward Traits: (All Growing Together)

Indicator, aka traits that only show the current confidence level:
High Confidence - trait_ChildConfidence_High
Neutral Confidence - trait_ChildConfidence_Neutral
Low Confidence - trait_ChildConfidence_Low

Reward after aging up:
High Self-Esteem - trait_reward_Child_Confidence_HighSelfEsteem
Low Self-Esteem - trait_reward_Child_Confidence_LowSelfEsteem

Childhood Phases: (All Parenthood)
Sorted by all -> children only -> teens only

Loud - trait_ChildhoodPhase_Loud
Mean Streak - trait_ChildhoodPhase_MeanStreak
Rebellious - trait_ChildhoodPhase_Rebellious
Picky Eater (A) - trait_ChildhoodPhase_PickyEater_A
Picky Eater (B) - trait_ChildhoodPhase_PickyEater_B
Picky Eater (C) - trait_ChildhoodPhase_PickyEater_C
Picky Eater (D) - trait_ChildhoodPhase_PickyEater_D
Picky Eater (E) - trait_ChildhoodPhase_PickyEater_E

Clingy - trait_ChildhoodPhase_Clingy
I'm a Bear! - trait_ChildhoodPhase_Bear

Distant - trait_ChildhoodPhase_Distant

As you can see, there are 5 different types of picky eater trait that the game can assign to the sim. All of them share the same gameplay, but it'll affect what food they'll like.

Character Value Traits: (All Parenthood)

Good Manners - trait_LifeSkills_GoodManners
Bad Manners - trait_LifeSkills_BadManners

Responsible - trait_LifeSkills_Responsible
Irresponsible - trait_LifeSkills_Irresponsible

Mediator - trait_LifeSkills_Mediator
Argumentative - trait_LifeSkills_Argumentative

Compassionate - trait_LifeSkills_Compassionate
Insensitive - trait_LifeSkills_Unfeeling

Emotional Control - trait_LifeSkills_EmotionalControl
Uncontrolled Emotions - trait_LifeSkills_UncontrolledEmotion

Soul's Journey: (All Life and Death)

Perspectives on Death - trait_MovingOn_PerspectivesOnDeath

Burning Soul - trait_MovingOn_BurningSoul

Reborn - trait_MovingOn_Reincarnated
Burning Soul (Reborn) - trait_MovingOn_BurningSoul_Reincarnated