Serrated Blade damage is used by the majority of charged melee attacks (such as the Orthos, Dual Ether, Gram, etc.). A few weapons, such as Dual Ether, also deal it as their default damage type. The majority of enemies regardless of their level will always receive full and unmodified damage of this damage type. Crawlers take a 1.5x damage multiplier from this and chargers, runners, and leapers take a 3x damage multiplier.
The Lanka and Flux Rifle recently gained this damage type, becoming the first ranged weapons to adopt it.