Active skill

Active skills, often referred to as skills, are abilities actively used by players and monsters, unlike passive skills. Active skills are typically gained by placing an active skill gem into an item socket. Some items also grant active skills through specific item modifiers.

Active skills can be augmented with support skill gems and used automatically with the trigger mechanic.

For item modifiers such as from Unnatural Strength, "skill gems" refers to active skill gems only. Conversely, support skill gems are referred to as "support gems" in passive skill and item mods, such as Catarina's.

Skill gems
All active skill gems grant active skills.

Enchantment mods that grant unique active skills
Glove Enchantments grant unique skills. These skills cannot be used directly, and can only be triggered.

Corrupted mods that grant active skills
By using a it is possible to receive the following active skills from corrupted items:

Legacy corrupted mods that grant skills
The following corrupted implicit mods have been drop-disabled since version 3.3.0. Players can trade with other players in the permanent leagues to obtain an item with these legacy mods. It is not possible to obtain legacy items with two corrupted implicit mods, as double corruption was introduced in version 3.3 (Incursion league).

Synthesis Implicts Active Skills
Synthesis implict mods can be found on synthesis unique items, added to items by Harvest craft, or found on legacy items in permanent leagues.