>>31205890Depends on the region. Here's an excerpt from the Unovan classifications.
Class 1: The pokemon is small, and would have a hard time opening a door unaided. Ex. Magikarp, Wishiwashi-solo, caterpie
Class 2: The pokemon can reach the knee of most adults, and can destroy tree stumps and other small objects. Ex. Zigzagoon, Sentret, Abra.
Class 3: The pokemon reaches the waist/ribcage of an adult, and can destroy furniture/medium objects easily. Ex. Machop, Deino, Monferno.
Class 4: The pokemon is about the same height as an average adult, and can destroy walls with some (but not taxing) effort. Ex. Gurdurr, Braviary, Graveler.
Class 5: The pokemon is taller and more imposing than an average adult, and could destroy houses if not properly managed.
Ex. Charizard, Wailord, Porygon-Z,
Class 6: The pokemon is very large and dangerous, and even their skilled trainers should be wary of letting them out near cities.
Ex. Hydreigon, Tyrantrum, Tyranitar, Gyarados, Wishiwashi-School.
A pokemon's natural inclinations also affect what class it falls into. There aren't many more dangerous than Class 6, and most of those are the subject of folktales.
