Oil GrenadeAttack, AoE, Projectile, Grenade, Fire, Duration Tier: 9 Level: 1Place into a Skill Gem socket to gain this skill. These are found in the Skill Gems panel.
The following support gems are recommendations by GGG as listed in-game, and do not necessarily reflect optimal combinations or the views of the wiki.
Gem tier
Support gems
I
EncumbranceEncumbranceSpell, Minion Tier: 1 Level: 1Supports any skill, causing inflicted Slows to be more powerfulDebuffs inflicted with Supported Skills have 15% increased Slow MagnitudePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Magnified EffectMagnified EffectAoE Tier: 1 Level: 1 Cost & Reservation Multiplier: 120%Supports any skill with an area of effect, making it larger.Supported Skills have 40% more area of EffectPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Second WindSecond WindTier: 1 Level: 1 Cost & Reservation Multiplier: 150%Supports skills with cooldowns, giving them extra uses of that cooldown. Cannot support instant or triggered skills.Supported Skills have 50% less Cooldown Recovery Rate Supported Skills have twice as many Cooldown UsesPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
II
Fiery DeathFiery DeathSpell, Fire Tier: 2 Level: 1 Cost & Reservation Multiplier: 120%Supports any skill that Hits enemies, causing enemies it Ignites to have a chance to explode on death.Enemies Ignited by Supported Skills have 60% chance to explode on death Explosion deals base Fire Damage equal to 10% of the Corpse's Maximum LifePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
IngenuityIngenuityTier: 2 Level: 1 Cost & Reservation Multiplier: 110%Supports skills with Cooldowns, increasing the rate at which those Cooldowns Recover.Supported Skills have 30% increased cooldown recovery ratePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Strip AwayStrip AwaySpell Tier: 2 Level: 1Supports Skills which apply Exposure to Enemies, increasing the effect of applied Exposure.Exposure applied by Supported Skills has 30% increased effectPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
III
Culling StrikeCulling StrikeAttack Tier: 3 Level: 1Supports Attack Skills, causing them to Cull Rare and Unique Enemies on Hit.Supported Skills have Culling Strike against Rare or Unique EnemiesPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
DiscombobulateDiscombobulateAttack, Physical Tier: 3 Level: 1Supports Attacks, causing them to build up Daze based on a portion of Physical Damage dealt.Supported Attacks cause Daze buildup equal to 100% of Physical Damage dealtPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Long FuseLong FuseGrenade Tier: 3 Level: 1Supports Skills which fire Grenades, causing those Grenades to have much higher duration and damage.Supported Skills have 50% increased Skill Effect Duration Supported Grenade Skills cannot explode before the end of their fuse duration Supported Grenade Skills deal 30% more DamagePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Item acquisition
Oil Grenade has restrictions on where or how it can drop.