Oil can be a good resource mostly seen in the ocean and rocks can give oil or triolbites can give oil to amonites can give oil too.
This can be found in one of the genesis 2 space biome rotations, and is farmed from rocks that look like a 3 year old has tried to paint them black
Just murder the sea pickles and get so much oil that America will want to know your location
Kill tek dino and harvest the dead body with your tamed dino(raptor,rex etc)(omnivor type,)
Everyone needs oil for late-mid-game, so make yourself some fur armor and go to the snowy areas, there is usually alot of oil rocks on the beaches. Use a metal pickaxe to harvest oil.
Kill basilosaurus= infinite oil
I think basliosaur actually drop oil naturally if you take it, not sure tough.
Dung beetles make some oil of ya give them poop.
There’s a bunch a black gloss rocks in the Arctic area, and those contain loads of oil. I recommend anky.