Yorbie: Episode One

Cogs and Energy drop off of all enemies in Yorbie. While Cogs are quite abundantly dropped by both enemies and crates, Energy is considerably harder to come by, and is best farmed on Insane difficulty as it is more common there (though still not near anything I'd consider truly "common"). I suggest not focusing too hard on this until after you've earned Insane Survivor if you're going for that, as that trophy will have you spending a good amount of hours in Insane mode.

If you're farming this, the best advice I can give is to play level 3 over and over again on Insane difficulty. Level 3 has many enemies while not being too difficult to complete, and lacks the turret section at the end of the level that is featured in level 1 and 2, making it ideal for farming.