Triglycerides (fats) contain mainly C-H bonds and little oxygen. Without fossilisation, plants (palm, maize, peacock, sunflower... and many more) produce them, and animals too (we build up grease for storage from nearly any excess food). Bees make wax, which comprises mainly monoesters, diesters, hydrocarbons, fatty acids.
More generally, life can and does make molecules that are very energetic. That's not a limit.