While the above list contains all of the most common simple possession charges, it does not contain all possible simple possession charges. Most of the most common charges come from the above list because they are considered the most "dangerous" drugs, and are classified as Schedule 1 drugs, meaning they are believed to be the most addiction-forming drugs available.
However, you can be charged with possession of drugs that aren't classified as Schedule I. Schedule II through V drugs can also carry possession charges. Drug types can range from fully illegal substances such as "magic mushrooms", to controlled substances like Adderall or Xanax. Being in possession of prescription drugs without a valid prescription is illegal.