let O CE be 0 AD, the canonical date of the birth and/or death of Jesus Christ (I forget which), roughly 1970 years of 365 days (not counting leap years) before the start of the Unix epoch.
Let’s define “natural” as “something that happened before major human civilization on Earth was a thing”, say, before -10 000 CE, and let's define “definitely not natural” as only started existing after being invented post-industrial revolution, so after +1800 CE.
Rape (animals do it)
Incest (animals do it, arguably some plants as well, depending on how you define plant filial relations)
Killing (both animals and plants do it, animals through violence, plants through poison. Fun fact: both nicotine and cafeine are made by their respective plants to prevent the plant from being eaten by various bugs and microganisms by poising the organism)
Eating dead things (animals do it)
Death (animals, plants, all living things do it)
Famine (animals die of starvationg)
Toxic chemicals, including nicotine, many opioids, and an immense pharmacy of chemicals that regulate human the human experience in an dazzling array of ways (living things create many interesting chemicals).
Safe, effective, highly available birth control
Postal systems
Widespread electricity, electric lighting
Universal health care
Supermarkets
Automobiles
Ambulances
Airplanes
Typing
The internet
Smartphones
Communicating via the internet, sharing knowledge with potentially billions of people, effortlessly