Respawn (Quest Monsters):

Ice Queen: Devias ~ 4h (DROP: Jewels)
Balrog: Losttower ~ 6h (DROP: Jewels)
Hydra: 8h ~ Atlans (DROP: Jewels)
Skeleton King: Elbeland/Noria ~ 12h (DROP: Exc Items)
Gorgon: Lorencia/Dungeon ~ 12h (DROP: Exc Items)
Red Dragon: Lorencia/Noria ~ 12h (DROP: Exc Items)
 

CountDown Invasions:

Metal Balrog: Lorencia, Noria, Elbeland (Random)
DROP - Ruud + Feather, Crest, W2.5 Combination Items; Special Jewel Random
 
Undine: Ubaid/Alkaamar
DROP - Ruud + Elemental Rune or Mithril; Special Jewel Random
 
Archeron x1: Debenter
DROP - Ruud + Pentagrama 180 (2sk-4skt); Special Jewel Random
 
Archeron x2: UrukMountain/Nars
DROP - Ruud + Pentagrama 180 (2sk-4skt); Special Jewel Random

Ferea: Ferea
DROP - Ruud + Random xAngel Item; Special Jewel Random

Nixies: Nixies Lake
DROP - Ruud + Random xAngel Item; Special Jewel Random

Deep: Deep Dungeon
DROP - Ruud + Random xAngel Item; Special Jewel Random

Dark: Swamp of Darkness
DROP - Ruud + Random xAngel Item; Special Jewel Random

KMine: Kubera Mine
DROP - Ruud + Random xAngel Item; Special Jewel Random

Elite Abyssal: Abyssal Atlans 3
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Canyon: Scorched Canyon
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Temple: Crimson Icarus
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Temple: Arenil Temple
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Ashen: Ashen Aida
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Burning: Burning Kethotum
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Ignis: Ignis Volcano
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Blood: Blood Tarkan
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Tormenta: Tormenta Island
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Elite Twisted: Twisted Karutan
DROP - Ruud + xAngel Item + Jewel + Sculpture + Guardian Enhanced + Uriel Feather + Ability Decision + Core Upgrade Stone

Muuns: Lorencia, Noria, Elbeland, Devias (Random); Losttower, Icarus, Aida, Kalima5 (Random); Kanturu, Kalima7, Swamp, Raklion (Random)
DROP - Ruud + Muuns PET