Let's review a general idea of what the types represent...
>Normal
Non-elemental, weird/type changing, and sound-based (unless two more dominating types prevail)
>Fire
Flame, magma, heat
>Water
aquatic life, creatures with control of water
>Electric
electricity, magnetism, sometimes light-related
>Grass
plants, fungi, creatures with control over these things
>Ice
ice, cold
>Fighting
martial arts (Western and Eastern)
>Poison
venom, poison, acid
>Ground
creatures that burrow, desert dwellers (often), mud, clay, sand (often, there's overlap with Rock)
>Flying
birds, flying creatures, wind
>Psychic
telekinesis, mental ability, cosmic power
>Bug
arthropods (usually, not always)
>Rock
stones, fossils/living fossils
>Ghost
ghosts, shadow, possession, the macabre
>Dragon
large reptiles and classic dragons, innate power, sometimes puns
>Dark
dirty tricks, negative emotion, darkness (in some cases)
>Steel
metal, durability, magnetism
>Fairy
fae, positive emotion, moonlight
For the most part, everything is covered. What isn't can surely be satisfactorily be put into one of the 18 types we have now.
