The traits added in-game by Additional Traits are :

• Handicaps
• Ephemeral : Leader Lifespan : -20 : Cost : +2
  
• Easily Distracted : Engineering Output : -5% : Physics Output -5% : Society Output : -5% : Cost : +1
  
• Simple-minded : Engineering Output : -10% : Physics Output -10% : Society Output : -10% : Cost : +2
  
• Lethargic : Energy : -5% : Army damage : -20% : Cost : +1
  
• Lazy : Minerals : -15% : Cost : +2
  
• Prodigal : Energy : -15% : Cost : +2
  
• Unfit Engineers : Engineering Output : -15% : Cost : +1
  
• Unfit Physicists : Physics Output -15% : Cost : +1
  
• Unfit Sociologists : Society Output : -15% : Cost : +1
  
• * Hateful : Other pop species happiness : -10% : Trust Growth* : -25% : : Cost : +2
  
• Hunter-gatherers : Food : -15% : Cost : +2
  
• Violent : Population growth : -15% : Other pop species happiness : -5% : Cost : +2
  
• Free Spirits : Population Governmental Ethic Attraction : -30% : Cost : +2
  
• Iconoclastic : Population Governmental Ethic Attraction : -45% : Cost : +3
  
• Delicate : Army Defense Damage : -25% : Cost : +1
  
• Weak Willed : Garrison Health : -75% : Army Morale : -20% : Cost : +2
  
• Very Slow Breeders : Population growth : -40% : Cost : +2
  
• Melancholic : Happiness : -5% : Pop Growth : -5% : Unity Prod From Pop : -10% : Cost : +2
  
• * Rooted : Colony development speed : -20% : Colony Ship Cost : +30% : Cost : +1
  
• Bitter : Food when used as livestock : -25% : +1 : Presapient only
  
• * Soft : Leader lifespan : -5 : Army Morale : -50% : -1
  
  
  
• Avantages
• Multitasking : Engineering Output : +5% : Physics Output +5% : Society Output : +5% : Cost : -1
  
• Easily satisfied : Happiness : +10% : Cost : -2
  
• * Born-Warriors : Army Damage : +10% : Army Morale : +10.0% : Fleet Damage* : +5.00% : Cost : -1
  
• * Sociable : Other pop species happiness : +10% : Trust Growth* : +25% : Cost : -2
  
• * Competitive : Influence Rivalry Gain* : +50% : Cost : -1
  
• * Aggressive : Rivalry max* : +1 : Cost : -1
  
• * Extremely Aggressive : Rivalry max* : +2 : Cost : -2
  
• * Belligerent : Influence Rivalry Gain* : +50% : Rivalry max* : +1 : Cost : -2
  
• Zealous Defenders : Garrison Health : +150% : Pop fortification Defense : +100% : Cost : -2
  
• * Lateral Thinkers : Navy Damage* : +8% : Cost : -1
  
• * Fast Analysers : Survey Speed* : +25% : Cost : -1
  
• Thermosynthetic : Food required : -35% : Cost : -3
  
• Doulophage : Slave food output : +15% : Cost : -1
  
• Passionated : Happiness : +5% : Pop Growth : +5% : Unity Prod From Pop : +10% : Cost : -2
  
• * Elusive : Ship Evasion : +8% : Ship Disengagement Chance : +5% : Cost : -1
  
• * Living Ships : Ship Hp Regeneration : +1% : Cost : -1
  
• * Mob Mentality : Fleet capacity : +10% : Navy capacity : +10% : Military (shipyard) building speed : +15% : Ship damage : -5% : Cost : -1
  
• * Pioneers : Colony development speed : +20% : Colony Ship Cost : -30% : Cost : -1
  
• * Influential : Influence : +20% : Cost -2
  
• * Planetary Designers : Terraforming Speed : +25% : Terraforming Cost : -15% : Clear Blockers Speed : +25% : Clear Blockers Cost : -15% : Cost : -2
  
• * Steadfast : Leader lifespan : +5 : Army Morale : +50% : -1
  
• Immune : Leader Lifespan : +40 : Habitability : +10% : -3
  
• * Sky Born : Ship Evasion : +8% : Strike Craft Damage : +10% : -1
  
  
• Presapients
• Natural Intellectuals : Society Output : +20% : Engineering and Physics Output : +5% : Minerals Output : -10% : Unity Output : +5% : Cost : -1 : Presapients only
  
• Natural Inventors : Engineering Output : +20% : Society and Physics Output : +5% : Minerals Output : -10% : Unity Output : +5% : Cost : -1 : Presapients only
  
• Natural Savants : Physics Output : +20% : Society and Engineering Output : +5% : Minerals Output : -10% : Unity Output : +5% : Cost : -1 : Presapients only
  
• Tasty : Food when used as livestock : +25% : Cost : -1 : Presapients only
  
• Bitter : Food when used as livestock : -25% : +1 : Presapient only

Handicaps
• Defective Scanners : Mineral Output : -10% : Cost : +1
  
• Weedkillers : Food Output : -10% : Cost : +1 : Robot-only
  
• Energy Leaks : Energy Output : -10% : Cost : +1
  
• Rusty Antiquities : Unity Output : -15% : +1 : Robot-only
  
• Insufficient Memory : Leader Skill Level : -2 : Cost : +2 : Machine-only
  
• Slow Processors : Leader Exp Gain : -6% : Science Output : -4% : Cost : +1
  
• Erratic Processors : Leader Exp Gain : -12% : Science Output : -8% : Cost : +2
  
  
• Avantages
• Customized Servitors : Owner Happiness : +10% : Cost -2 : Robot-only, no full-rights.
  
• Multithreading : Leader Exp Gain : +6% : Science Output : +4%
  
• Planetary Gardeners : Terraforming Speed : +25% : Terraforming Cost : -15% : Clear Blockers Speed : +25% : Clear Blockers Cost : -15% : Cost : -2 : Machine-only
  
• Swarm : Army damage and Morale : +25% : Robot build speed : +50% : Mineral output : +25%, Unity output : -10% : Science output : -30% : Cost : -1 : Machine-only : PROBABLY OVERPOWERED AND SOON TO BE REBALANCED

The traits marked by a * are using an event which check at game start, when you modify your species and once a year that your main species still possess the trait. These traits apply to the whole empire.
Hateful, Violent, Aggressive, Extremely Aggressive, Competitive, Belligerent and Sociable traits gives opinion modifiers, like Charismatic and Repugnant does.