Audit this list for Grammar/Prose, and if I missed any attacks generally shared by ALL members of a type (or a sufficiently high percentage like 90%), make a note of it on the type.
Type Bonuses:
Typing is very important in Pokemon. A Pokemon's type is determinant largely on their genetic structure and the environment around them. Different types have adapted to different environments in a multitude of ways. Here are the bonuses based on those innate abilities:
STAB (Same Type Attack Bonus): When using a damaging or non-damaging move of the same type as the Pokemon, Energy Cost is reduced by 1. Damaging attacks have 3 more Base Attack Power regardless of the initial attack strength. Certain STABs may allow certain moves to keep their focus in all conditions, except when struck by a multi-hit attack (which always disrupt these moves). Whenever using one of the attacks below, moves of their STAB will not break any required focus unless it would directly alter their continuance of the attack.
Partial Trapping Moves: Pokemon will have a much easier time using commands that don't use the appendages sourced in these attacks or else will be able to maintain their mental focus while using other attacks. This effect applies to Bind, Fire Spin, Clamp, Magma Storm, Sand Tomb, Whirlpool, and Wrap.
Uncontrollable Attacks: Pokemon will not be subject to the disruption of Petal Dance, Outrage, and Thrash when hit by moves with greater than 12 Base Attack Power.
Skin notes: The term skin is used often in these descriptions. Please note that these descriptions are generally reserved for pokemon purely of that type. Pokemon with dual types can have their skin features modified greatly, or the Pokemon's skin may even by unique to the species such as Parasect and Toxicroak. Nonetheless even Pokemon of dual types will retain the primary defensive qualities of both of their skins' type. Rock/Steel skin for example is made of an alloy that prevents toxins from seeping in but does not scatter flames as much, thus retaining the immunity to poison status and the buffering ability in Sandstorm while being neutral to flame attacks rather than resisting them.
In addition to STAB, some types have developed other traits to help them cope with life in the wild.
Dark
Dark:
Dark types are often portrayed as inherently malevolent, but this is not the case. What Dark types do posess is a fierce mental presence that makes them immune to the effects of psychic suggestion and control. This presence also disables psychic waves surrounding an incoming object, stopping it dead in its tracks as it falls harmlessly to the ground. Dark types are nocturnal for the most part, and thus battle very effectively in caves, at night, or in otherwise darkened conditions. While any total darkness will do, dark types are also the best at navigating confusing half-light situations such as twilight or dawn battles, where shadows can confuse or disorient other Pokemon. This perception does not necessarily extend to structural problems deep in caves, as while Dark-types can discern anything in their immediate vicinity, they aren't naturally in-tune with the echoes of earth vibrations. Dark types are very vengeful by nature and happily use retaliatory attacks. Dark types are also more endeared to trickery and deviousness, and can use attacks like Nasty Plot and Taunt even if infatuated.
Summary: Dark STAB; Immunity to all telepathic and telekinetic attacks, better performance in all darkened and especially twilight conditions. Can use any Dark-type attack regardless of Attraction.
Fire
Fire:
One of the basic elemental types of Pokemon, Fire-types are noteworthy for being much more energy-oriented than most of their fellow Pokemon. While other Pokemon are mostly physical mass, Fire-types are an energy powerhouse not unlike their Electric brethren, but the constant erratic nature of fire is much harder to contain. As a result, Fire-types heat the air surrounding their bodies to about 90 degrees Farenheight when at rest. Their flames are often just irradiated energy taking that form and are above your average room temperature, but by no means lethal or even particularly dangerous. Fire-types emit a low glow in dark places with or without an open flame, which does light the area around them somewhat but also gives away their position. At high levels, Fire types can also utilize energy from the sun to maintain and augment their energy, utilizing the sun's natural radiation.
In battle their irradiated energy changes quickly however, and Fire-types can emit heat from their attacks that easily burns skin, melts rock, or otherwise does intense external damage to the various matter/energy constructs of Pokemon skin. Fire types themselves are immune to burning, and highly resistant to freezing (though it is not impossible if a limb without an open flame is targeted). Strong fire attacks can easily overpower weaker water attacks, despite the type disadvantage. Most Fire types can swim, however if they have open flames active (rather than irradiating) they will take small amounts of damage. Fire attacks cannot be used effectively underwater or in space (why would you battle in space dummy!), as they require oxygen for combustion. During Rain, any active open flames will emit steam, while irradiated energy will give off no signal of being effected. The Fire-type is not damaged by rain, although obviously their Fire attacks will be greatly reduced in effectiveness.
Summary: Fire STAB; immune to burn, 50% reduction in freeze chance, emit a low glow in dark places, takes additional damage if active open flames are exposed to a water attack. Superior senses in volcanic or brushfire areas.
Ghost
Ghost:
Ghost Pokemon are the most enigmatic type. As a whole they possess a broad range of supernatural abilities from intangibility to various kinds of psychokinesis to mere illusion, however these effectiveness of these strange abilities largely depend on the individual Pokemon. Ghastly, Haunter, and Gengar are the least tangible of any ghost, and can pass through walls for a brief period of time without exhausting themselves. Ghost types are particularly adept at a few other tricks, including the ghostly flames of Will-o-Wisp, employing the shock value of Sucker Punch, utilizing Telekinesis and Psychic, and various other Trick-ery.
Unfortunately, due to their build, Ghost types with secondary typings (bar Gastly, Haunter, and Gengar) cannot go through walls, however they can briefly become briefly intangible. Most types have evolved around the annoying habit of Ghosts to become intangible and have attached an energy signature to their attacks that strike ghosts in an intangible state. Normal and Fighting types remain the only Pokemon that rely on direct brute force, and Ghosts simply absorb the ki used in some fighting attacks without effect.
Summary: Ghost STAB; brief intangibility that nullifies Normal and Fighting-type attacks. Can move through walls for a brief period of time but must remain in motion. Superior senses in low light and inside dark buildings. Have no vision reduction in hazes.
Ground
Ground:
Most Ground-type Pokemon have a strong attachment to deserts, caves, and other dry areas where they make their burrows. What few exceptions there are crave muddy wallows to call home. While Digging to evade an opponent, Ground-type Pokemon only suffer a 2 energy per action drain compared to the 3 energy per action drain experienced by opponents less in tune with the earth. Ground types are used to navigating underground in dark places, and thus have better vision in tunnels and underground caverns. This is unique from Dark-types, who can use total darkness or confusing half-light in any context, but are not particularly in tune with earth movements. Ground types require their surroundings to be largely tunnels and other earthen formations to be effective at utilizing their underground "night vision." While most Pokemon with wings or Levitate can avoid Ground's strongest physical attacks, Earthquake and Magnitude, Bone Club/Merang/Rush, Dig, Earth Power, Mud Bomb/Shot/Slap can still hit them effectively. True Flying types are the only Pokemon that seem to be able to intuit damaging Ground attacks perfectly and have the agility to dodge them. Ground types have thick, watertight skin that acts as a grounding agent against electric attacks, which never penetrate and instead just follow along the outside harmlessly into the ground. Although the skin is watertight, it must be kept dry because it cannot completely keep water out forever, and has a spongy quality when drenched. Rain alone will not agitate the skin enough to bring on this effect, although it does make Ground types uncomfortable. Ground types also have an excellent sense of the rock formations around them, and can easily use several Rock moves to augment their offense.
Summary: Ground STAB; Immune to all electrical attacks, can Dig through almost any substance, Evasive Digging reduced from 3 per action Energy Cost to 2 per action, superior senses in darkened cave surroundings.
Poison
Poison:
Poison shares a lot in common with Normal, at least as far as being generalist and having poor super-effective coverage. It's greatest advantage though is its complete immunity to toxins. Poison types can survive in toxic waste sites, deserted city dumps, abandoned playgrounds, anywhere pollution drives out other Pokemon, Poison types thrive. Poison types will never choke on or be blinded by smog, smokescreens, sludge, or anything other than direct solid material (such as sand or mud) into their eyes. Other common poisonous critters are snakes, who in addition to their toxic tendencies can also squeeze the life out of opponents or paralyze them with a snake glare.
Summary: Poison STAB; immunity to Poison/Toxic, see and breath through smog/smokescreens/haze uninhibited. Able to use Wrap and Bind without losing focus. Superior senses in urban settings.
Psychic
Psychic:
What Fighting is to physical prowess, Psychic is to mental. Psychic types sense opponents energy in addition to any visual or hearing confirmation, allowing them to strike opponents from a great distance with their mental assualts and strike them even if they are physically blinded or inhibited. The same is not true if their mental concentration is disrupted through aggravating sounds. They also have a great deal of their own support moves, rivaling those of the Normal type. Psychic Pokemon are deep into mental energy, and thus they can also use ki attacks fairly effectively. Psychic types have instensely strong minds, and can fling opponents with Psychic attacks that their non-Psychic counterparts cannot.
Psychic-type attacks are not godlike, however. Most of them are simple mental assaults that tap into one of the opponents fears or memories. Extrasensory for example taps into memories that frighten the Pokemon, causing them to flinch. Psychic recalls moments of weakness that can lead to a lowering of special defense, and confusion using attacks generally just garble memories. While Psychic (the attack) can redirect energy attacks somewhat, it must be focused on the attack, not the Pokemon issuing it in order to have any function to that effect.
Summary: Psychic STAB; less susceptible to blinding, more susceptible to sound-based assaults as far as locking on with Psychic attacks, can lift and throw opponents with Psychic attacks regardless of weight difference. Psychic-type attacks are not godlike and cannot be used as a catchall for Disabling, Binding, and redirecting opposing attacks.