I created this (unfinished) table for an article about Type Origin I want to be on Bulbapedia. I need to put it somewhere else I think, but I guess it'll be fine here for now:
Type Origin
| Type | Beings | Action | Element | Environment |
| Fighting | x | Fighting | Aura/Martial Arts | x |
| Flying | Birds | Flying | Air/Wind/Sound* | Sky |
| Dark | x | Cheating/Stealing | Evil (Dark)/Disaster/Negativity | x |
| Electric | Bioelectrogenetic Animals | Shocking/Charging/Draining Electricity | Electric(ity)/Energy/Static Electricity/Light** | x |
| Steel | Robots/Knights and Other Armored Warriors | Hardening | Metal/Steel | Industry/Artificial Environments |
| Rock | Living or Resurrected Fossils | Polishing/Sculpting | Stone/Rock | x |
| Ground | x | Digging | Earth/Sand/Ground/Land/Mud/Bones/Soil | (Under)Ground/Land |
| Ice | Polar Animals | Freezing | Ice/Cold | Polar Regions/Frozen Landscapes |
| Psychic | Aliens | Mind Reading/Future Seeing/Mind controlling | ESP(er) (Psychic)/Mind/Spirit/Time/Genetics/Emotions | Space |
| Fire | x | Burning/Heating/Fire Spitting | Fire (Flames)/Magma/Heat | Volcanos |
| Water | Fishes and Other Aquatic Animals | Swimming | Water/Rain | (Under)Water/Sea/Ocean/Rivers |
| Grass | Plants and Mushrooms | Photosynthesizing/Growing | Vegetation/Grass/Wood | Woods/Forests |
| Dragon | Dragons | Dominating | Power/Might | x |
| Ghost | Ghosts | Passing Through Objects/Scaring | Death | Graveyards |
| Normal | Pets | Moving | Physics/Sound*/Light**/Love***/Matter/Default/Normal(ity)/Speed | Towns |
| Fairy | Fairies/Magical Beings/Elves/Angels/Cute Beings | x | Life/Love*** | x |
| Bug | Insects, Arachnids and Gastropods/Bugs | Leeching | x | x |
| Poison | Living Waste | Poisoning/Stinking/Rotting | Acid/Poisons | x |
- *Sound seems to switch between Normal and Flying.
- **Light seems to switch between Normal and Electric.
- ***Love could become part of Fairy in Generation VI.
- A Pokémon’s type is decided by:
- What for kind of being the Pokémon is (based on).
- What for kind of action the Pokémon (is able to) perform(s).
- What for kind of element the Pokémon (partially) consists of, possesses, represents or contains.
- What for kind of environment the Pokémon lives in, is commonly found in, protects, represents or rules over.
- Sometimes a Pokémon would get more than three types, considering the above list; in that case the two most important features of a Pokémon are taken into consideration. (Charizard; Beedrill) Exceptions are when the balance or expansion of the type combination chart is more in favor. (Stunfisk)
- Sometimes a Pokémon that could easily get two types, considering the above list, only gets the most important or most relevant one. (Glalie; Cofagrigus; Voltorb; Pikachu; Marill; Growlithe) A Pokémon may still obtain the second type upon Mega Evolution. (Ampharos)