Slots with a given mod slot are mutually exclusive. The slot names are arbitrary. The same mods on different items do not stack. So two resource hauler or two O2 boosted do not give additional benefits.
Ablative [13369c] suit
- -15% incoming Energy damage.
Anti-Ballistic [13369e] suit
- -15% incoming Physical damage from ranged weapons.
Beast Hunter [1336bd] suit
- -15% damage from Alien enemies.
Chameleon [1336c1] pack,suit
- Blend with the environment while sneaking and not moving.
Combat Veteran [1336be] helmet
- -15% damage from Human enemies.
O2 Boosted [690b0] helmet,pack
- +20% oxygen capacity.
O2 Filter [690ae] pack
- -25% oxygen consumption.
Sturdy [133699] suit
- -15% incoming melee damage.
Analyzer [690af] helmet
- +10% damage to scanned targets.
Antiseptic [710fa] pack
- +25 Airborne Resistance.
Auto-Medic [c9a43] suit
- Automatically use a Med Pack when hit and health is below 25%, once every 60 seconds.
Fastened [2ede4e] pack
- +20 carry capacity.
Hacker [2c43da] helmet
- +2 max auto attempts that can be banked while hacking.
Resource Hauler [60293] suit,pack
- Resources weigh 25% less
Weapon Holsters [60295] suit
- Weapons weigh 50% less.
Armor-Plated [2ede59] pack
- -10% incoming Physical, Energy, and EM damage.
Incendiary [2983][7d728] suit
- 10% chance to ignite nearby attackers.
Mirrored [59ae8] suit
- 4% chance to reflect attacks.
Peacemaker [2d01a2] suit
- Rifles do 10% more damage.
Reactive [6029f] helmet
- 10% chance to stagger nearby attackers.
Repulsing [6029d] pack,suit
- 5% chance to disarm nearby attackers.
Sensor Chip [2c43db] helmet
- +20% accuracy while firing on the move.
Sentinel [be540] suit
- 75% chance to reduce damage by 50% while standing still.
Slots with a given mod slot are mutually exclusive. I have yet to determine the slots for these modifications. The slots align directly with the armor ones (slot A armor is slot A weapon) for mixed mods.
Anti-Personnel [ff442]
- +10% damage against humans.
Bashing [fea07] pistol
- Deals double damage when gun bashing.
Berserker [f437e]
- Does more damage the less armor one has.
Cornered [f428e]
- Damage increases as health decreases.
Disassembler [1625eb] heavy
- +30% damage against robots.
Extended Magazine [ffa3b]
- Doubles the base magazine capacity
Exterminator [15dd18] melee
- +30% damage against aliens.
Furious [ea117] pistol
- Each consecutive hit deals more damage.
Instigating [f2013] melee,pistol
- Deals double damage to target with full health.
Space-Adept [f7321] heavy,pistol
- +30% damage while in space, and -15% damage while on a planet.
Corrosive [8ab47] melee
- Randomly deals corrosive damage and reduces the targets' armor over 6 seconds.
Crippling [f2e39]
- Deals +30% damage on the next attack after hitting a target's limbs.
Handloading [ea0ba]
- Volatile rounds that are designed to pack a bigger punch, but aren't as stable and can fail on occassion.
Hitman [122f1c] rifle
- +15% damage while aiming.
Incendiary [7d728] heavy,pistol
- Randomly deals incendiary damage.
Lacerate [fea49]
- Randomly applies a bleed effect to the target.
Med Theft [ffa3c]
- Chance that humans drop extra Med Packs on death.
Poison [319aec]
- Randomly deals poison damage and slows the target.
Rapid [fea04]
- +25% increase in attack speed.
Staggering [e8d64]
- Small chance to stagger enemies.
Concussive [fbd3c] heavy
- Small chance to knock down targets.
Demoralizing [fc884]
- Small chance to demoralize a target.
Explosive [fa8d6]
- Randomly switches to explosive rounds.
Fenzy [fc8a4]
- Small chance to frenzy a target.
One Inch Punch [f4cf0] pistol
- Rounds fire in a shotgun-like spread.
Shattering [f4557] rifle
- Break through even the strongest armor.
Skip Shot [31c0c4]
- Every fourth shot fires two projectiles at once.
Tesla [31c0c6]
- Rounds will sometimes emit electricity where they land that damages and slows nearby targets.
Titanium Build [ffa3d]
- Premium build materials make this weapon light as a feather.