Use community resources like the Blight Helper or PoEDB to search for specific passives or tower modifiers.
Hold the Alt key while hovering over a Notable on the passive tree to see its oil requirements. poe-oil-enchants
Items like Stampede boots or Breathstealer gloves can also be anointed with three oils to gain a Notable Passive. How to Find Recipes Use community resources like the Blight Helper or
The number of oils required depends on the item type being enchanted: poe-oil-enchants