Could someone tell where the ♥♥♥♥ I get flawless sentient cores?

[XXX_SniperSlayer42069_XXX]

or even exceptional ones..

[Ecgtheow]

From eidolon hunting

[Heartnet]

exceptional dorp eidolon teralyst body parts each one if u want flawless u need to kill eidolon teralyst but last hitting to the eidolon bait drones its changed death animation and more loot