In AKIRA, at the moment of the greatest release of energy, everything is reduced to a bright white. Maximum glow for maximum power.
As the trope image shows, the holy Gold Clothes(armors) from Saint Seiya sometimes glow...very much so.
Gourry in Slayers has an extremely powerful Sword of Light, much better than any other regular swords. He can chop through trees with his sword, and we're not talkin' fist-width saplings, either. It also makes lightsaber noises.
Everything that has some sort of spiritual nature in Earth Maiden Arjuna gives off an awesome glow. Including Juna's Magical Girl transformation, as well as her energy bow Gan Deeva.
Ea, Gilgamesh´s EX+++ Noble Phantasm turns the winds it sends out red.
Some Initial D characters can tell roughly how good another driver is by the glowing aura around the driver and by extension, his car when the person is driving it.
Yu-Gi-Oh!! does this for several reasons. Spell and Trap cards glow whenever their effects come into play as well as various monster attacks. Millenium items often glow in order to show they are being activated. Noteworthy glows come from whoever is summoning God cards.
Yu-Gi-Oh! 5Ds does this very frequently. Shooting Star Dragon is in constant glow mode and is only ever seen once without it. The final battle with ZONE has Yusei tune all 5 of his friends' dragons into Shooting Quasar Dragon, the most overly glowing transformation sequence in the series, as it involves Yusei and his D-wheel going fully gold. One might be able guess it has whole arsenal of effects ready to beat ZONE's Timelords like they were nothing.
Many attacks in Pokémon glow (insert color here) before making things explode and blast off (Iron Tail, Focus Punch, Bubblebeam, etc).
Within the TCG, Holographic cards are generally considered to be powerful, or at least rarer than their non-holographic counterparts.
Used in the Suzumiya Haruhi Brigade-movie "The Adventures Of Mikuru Asahina", just like any other cliche-trope. When Koizumi's power is released, he glows blue-ish. Interestingly though, it does not appear to be the comically used Special Effect Failure, like with the Mikuru-Beam.
If you notice yourself being bathed in a soft, pink light in Magical Girl Lyrical Nanoha, that is your signal to run fast, and run far, as that soft light won't stay soft for long for it comes from the massive pink glow that precedes Nanoha's Starlight Breaker.
If you find yourself in a similar situation in Dragon Ball Z, you're about to be blown up by Majin Buu. Generally speaking, soft, pink light is best avoided in Anime.
Performing alchemy causes stuff to glow in Fullmetal Alchemist. This is actually used as a small plot point when Ed realizes that he and Al can't use alchemy to sneak into the fifth laboratory, as the guard would see the glow.
Bleach will sometimes use this trope to display the power upgrade the release of a shinigami's zanpakutou or an arrancar's resurrecion may cause.
Getter Robo has this for Getter Rays use. Most designs of Getter-1 even include several clear panels on the face and some on the chest and limbs so they can light up when it's time to kick ass.
Actually inverted in the Android saga. The titular androids - cyborgs more powerful even than Frieza - are shown as extreme threats, despite their lack of any glow at all. In fact, Androids 17 and 18 are for a short time the two strongest beings in the DBZ universe, the latter totally trouncing the very glowy, newly Super-Saiyan Vegeta.
This is because the glowing Battle Aura's are a product of ki energy, the source of nearly all DBZ fighters' superhuman powers. All, that is, except the Androids. The fact that their power is so different in nature was part of what made them so dangerous: all of the heroes can sense powerful ki from miles away, but one of the Androids could be standing right behind them and they wouldn't even know it. Which is exactly what happens to Yamcha. The results include a fist-shaped hole from his back to his chest.
Inverted again in the Buu saga. When Gohan achieved a new level of power beyond the glowy Super-Saiyan or even the glowier and sparky Super-Saiyan 2, his hair remained black and had almost no battle aura to speak of.
In Dragonball GT, both Goku and Baby as Great Apes have a golden, glowy aura and fur. Seeing as this is basically Super Saiyan Great Ape, it makes sense.
The Rebuild of Evangelion movies introduce this in spades. The most obvious example is what happens to Unit-01 at the end of the second movie: it starts going berserk and gets the usual Glowing Eyes of Doom. But so does its pilot. And the mecha's fluorescent green parts starts glowing sickly red. As well as the inside of its maw. Then it rebuilds its amputated arm as a glowy, proteiform appendage, grows a halo, shoots Eye Beams left and right and lose its armour only to reveal glowing white patches beneath it. By the time the credits flash, it has become a giant glowing figure of pure white. Unsurprisingly, its opponent is unable to resist such a brilliant display.
Darker than Black is rather fond of this trope. Contractors using their powers glow blue (identified as Cherenkov radiation), and their eyes start shining red. Even more extreme when Hei gets a bit upset near an Amplifier Artifact, which makes the entire neighborhood glow.
This is lampshaded when Naruto's controlled form of the 9-tails's chakra is actually used as a flashlight.
A the Fourth Raikage's Raiton: Yoroi (Lightning Armor) cover his body in lightning.
In YuYu Hakusho, B Class and higher beings like Toguro, Yusuke, Bui, and Sensui often display bright auras when either manifesting their full power or when using a powerful attack. Especially powerful auras can cause adverse things to the wielder's surroundings: Toguro's can disintegrate anything drastically weaker than him, and the combined power of Sensui's Sacred Energy and Yusuke's new-found demonic power created massive earthquakes and twisters strong enough to kill A-Class beings in an instant.
Then there's the ultimate attacks of the titular Super Robot in GaoGaiGar: Hell and Heaven has one fist glowing red and the other glowing yellow, while using the Goldion Hammer results in the entire robot glowing gold. This is then taken Up to Eleven in the OVA FINAL, where they introduce the world's biggest ban hammer that has a head several magnitudes larger than the handle and is made up of nothing but pure, glowing energy.
The Spiral Energy of Tengen Toppa Gurren Lagann. While the glowing energy powered by Fighting Spirit(aka. Pure Manliness), is present from the first episode, it reaches new extremes nearly every other episode, until by the end, the main characters are piloting a Humongousmecha 100 times the size of THE MILKY WAY GALAXY, which is not even actually a machine but a materialization of Spiral Energy. Its energy-based nature is shown by the fact that the torso of the mecha is mostly comprised of a flaming, glowing mass Spiral Energy.
During key battles in Digimon Adventure digimon will sometimes start glowing with holy power.
Subverted in Rising X Rydeen. Takara gets worried when Golden Lion King starts roaring and glowing brightly. Takara thinks he's about to use a powerful attack but Mission Control reveals to Takara that it's actually just Golden Lion King's power, roaring makes him glow.
Pretty much a common trope in comics, especially as regards Psychic Powers. One should apparently be able to spot a telepath with ease thanks to the glowing energy field that emanates from their heads and usually flows out from them around the heads of those that they are using their powers on. Telekinesis likewise tends to consist of a colored energy field surrounding the affected objects. This does however depend somewhat on artistic preference of the creators:
This has become more and more common over the years in Marvel Comics, to the point where virtually any use of a super power will glow, even if the energy involved (magnetic, psionic, etc.) should not be visible to the naked eye. Justified due to Rule of Perception (i.e. the glow is the visual cue to the reader that something is happening.)
Amusingly, this one tends to vary a great deal with the depiction of the Invisible Woman of the Fantastic Four. Often her force fields, which are supposed to be invisible, were drawn with dotted lines or shading so that the reader knew where they were, even while it was presumed that characters could not see them. This invisibility was used dramatically during John Byrne's run, where the identity of the super-villain Malice and her powers were a mystery as she systematically took down the members of the team using completely unseen forces. It is only when Daredevil, who "sees" via a radar sense, shows up and asks about the "amorphous blob" they are fighting that they realize that it is Sue and her invisible force fields, thus saving the team from another Reed Richards Is Useless incident. More recent depictions, however, sometimes show Sue's power as a crackling energy field, not unlike those of other psionic characters.
In the early days of the X-Men comics, the powers of characters like Magneto, Marvel Girl and Professor X were often depicted with wavy lines, implying that they were not visible to others characters. Now they cannot seem to use their powers without unleashing incredible amounts of glow. This has been especially true whenever Jean (or anyone else) is channeling the Phoenix Force. In that case just performing a simple mindlink will result in actual flames flowing between them and the other person.
Notably inverted in some Valiant Comics prior to the takeover by Acclaim. Powerful psionics such as Toyo Harada and Peter Stanchek gave off no glow even when performing massive feats of power such as levitating large objects or ripping apart buildings. However, this trope was very much in force with Solar and Mothergod, whose power to manipulate all forms of energy was usually accompanied by geometric patterns of rainbow light.
Literally; in The Sandman graphic novel Endless Nights, an Oan precursor of the Guardians of the Universe manipulates a primitive form of Green Lantern energy which she calls "the Glow". Her name? Killalla of the Glow.
In Power Pack, Katie's (Energizer) power causes her to glow when she absorbs... just about anything; she's also able to shoot energy balls. The brighter the glow, the more power she has stored up.
Played for laugh in the French comic Dungeon Zenith vol. 2: The Barbarian Princess: the hero asks its speaking sword whether it has special powers. Yes: it glows in the dark. Enough to make him a target, not enough to be used as a light.
Doctor Strange typically has a glow around his hands when spellcasting.
In All Fall Down, Siphon exhibits this to a blinding degree shortly before she dies.
The Sentry is not called 'The Golden Guardian of Good' for nothing.
The fact that the protagonist of this particular Dragon Age fanfiction gets his magic from a fairly unstable tear in the Veil, which he has in his body, means, among other things, that he starts glowing white whenever he does something unusual, either just from the eyes or his whole body, up to looking like a Stargate ascended ancient.
In the second Pokémon movie, to save Lugia, the three legendary bird Pokémon, and resolve all conflict, Melody had to play a tune on what looked like some sort of ocarina. The stones she played it next to glowed depending on what note she used, and then glowing water came out from nowhere and entered into the sea.
In Tangled, Rapunzel's golden hair glows whenever she uses its powers of healing and immortality. She manages to take advantage of this when she and Flynn get trapped in a flooding cave and need to find a way out.
Flower, gleam and glow Let your power shine.
In WALL•E, not only does EVE glow very faintly (the better to invoke a Gaussian Girl), her presence and touch cause electrical lights to glow as well.
Films — Live-Action
The lightsabers in Star Wars are the logical conclusion of this phenomenon. No other weapon can beat a sword that's actually made out of glow!
In the 1985 film The Last Dragon, there is The Glow: when a fighter's hands glow, he is among the best in the world - when his entire body glows, he IS the best. Sho'Nuff, the Shogun of Harlem, demonstrates the former towards the end of the movie, but Leroy "Bruce Leroy" Green demonstrates the latter after a beatdown.
Tony Stark's arc reactor in the Iron Man movies glows very blue. Very vaguely justified in that it is producing electrical energy, and that whatever reaction happens in it might give off Cherenkov radiation. As for the repulsors... the workings of a palm-sized rocket/energy weapon are anyone's guess.
From the same continuity as the above: The Tesseract from Captain America: The First Avenger. At the start of the film, Johann Schmidt comes across the artifact buried in the tomb of a Norwegian warrior, but we know it's fake because it doesn't glow. The real one, on the other hand, is like a small star. The glow extends to Arnim Zola's Tesseract-powered weapons as well, all of which carry luminous blue power packs.
Inverted in Indiana Jones and the Last Crusade, where the actual Holy Grail is the most mundane-looking wooden cup yet the gold-colored lining of the True Grail makes it appear to glow from the inside.
Gandalf invokes this trope when he adds lighting to explain the disappearance of Bilbo in his Birthday party. After Gandalf's resurrection, his increased power makes him emit illusory sunlight.
Mocked in A Song of Ice and Fire when Stannis gets Lightbringer, a literal glowing sword, but despises it because it doesn't do anything else better than most swords.
It is speculated that this is because it isn't the true Lightbringer, which would probably glow, but would actually be hot as well. So Power Glows, but so does a cheap glamour. Although it's worth noting that so far none of the actually superior swords have glowed.
Played straight with Melisandre's ruby. Whenever she causes weird magical stuff to happen, her ruby choker is said to glow intensely.
In The Dresden Files Harry more than once makes his staff/blasting rod glow, usually when he is about to smash something into the water table.
Also his much abused amulet, which glows whenever he uses it as a light/silver bullet against superpowered werewolves.
Then we have the Swords of the Cross, all of which glow with varying intensities depending on the wielder and situation. For instance Amoracchius once shines so brightly that it chargrills many light hating hobs from 20 feet away. Similarly, when Murphy draws Fidelacchius it glows brightly enough to scare off Deirdre.
Any time Harry uses Soulfire or Hellfire.
When Harry starts training Molly to use her magic she had a tendency to glow when excited. This was fixed after the first few weeks of training
Subverted several times in the Discworld series. Because of the world's narrative causality, mundane items wielded with true conviction are often stronger than fancy magic weapons.
Justified in the case of Death's scythe and sword, since these are so sharp, they cut up the air molecules that happen to bump against them. This, of couse, causes lightning-like ionization.
All magic produces bright glows in Elantris, because it is the sign of the power of the Dor breaking in to the physical world. The most powerful practitioners of magic, the Elantrians actually glow non-stop, but other magic-users produce light with their powers as well.
Interestingly the glowing caused extra problems when the magic went away because The glow attracted a fungus which fed on and enhanced the light. When the magic failed and the glow disappeared the fungus died and rotted, coating all of the surfaces of Elantris in slime. This slime is partially responsible for why the city looks so much more decrepit than it should be.
Stormlight, the primary magic power of The Stormlight Archive, glows, as one might expect from the name. A slight subversion in that most people use the glow more than the power itself, though it can be used to run Magitek.
Katherine Kurtz's Deryni can produce spheres of cool light (called Hand Fire), and they can manifest glowing auras around their bodies. Ritual circles (and dueling circles) appear as glowing light. Colours tend to be hereditary (Haldane red, Corwyn green), and certain colours (green, silver, gold) are associated with Healing ability.
Deconstructed and Played for Drama in Jessica Amanda Salmonson's The Golden Naginata: Unless it has been used to wound the kirin who guards it within the past month, the titular weapon's glow is so bright that it blinds anyone who sees it.
More powerful Wizards like Septimus and Marcia in Septimus Heap get enveloped in a purple aura when they are spellcasting.
Invoked in Dream Park, as holographic auras of appropriate intensity are overlaid on Gamers' bodies when they activate their characters' magic.
"Wild Cards" has the GoldenBoy Jack Braun, whose body is surrounded by a golden aura whenever he uses his abilities or is under attack. Surprisingly, the field activates whenever there is a threat to Jack, even if he doesn't know about it, or in mundane situations like if his razor were to slip while shaving.
Many of the spells in Harry Potter take the form of beams of light, and many more glow.
Played straight in The Elenium and it's sequel The Tamuli. Several spells that the Knights and Sephrenia use create a light, but none are on par with Xanetia, who's entire body glows when she unleashes her power. Toyed with on the spiritual level, as Xanetia's power comes from a curse that renders her dark and undetectable, while the magic the others are blessed with shine and ring out for others to notice.
Nicolae Carpathia in the Left Behind book Armageddon gives off a burnt-orange glow while he and most of his Global Community cabinet are stuck in New Babylon during the Fifth Bowl Judgment that causes complete darkness throughout the whole city.
In Smallville, the usage of some meteor powers cause glowing, but Chloe's healing powers is most notable. Fracture shows that pure white light is literally shone on everything in the mind world of whoever she is healing, while most meteor powers glow green.
In Stargate SG-1, the glowiness of a power source is directly proportional to how powerful it is. The most powerful, Project Arcturus, creates a giant glowy ball of pure energy.
Lampshaded in a later episode where determining whether a super powerful artifact is safe to handle amounts to "Well, it's not glowing anymore, so..."
When someone glows on Doctor Who, something Bad Ass is about to happen. Cases in point, the Bad Wolf and psychic supercharged Doctor.
In Madan Senki Ryukendo, the Ultimate form of the title hero is ridiculously shiny, and his final attack even moreso.
In Star Trek: The Next Generation, the Warp Core of the Enterprise has a band of glow running down it. The faster the Warpspeed, the faster-moving the glow. Star Trek does this a lot to show that things have power behind them.
That could simply be an indicator light.
It appears that electrical machinery also has an electromagnetic aura when viewed through Geordi's VISOR, as we got to see in one episode which gave us a perspective that went -quite literally- through his eyes. This includes the android, Data. Geordi is rather surprised to find that nobody but him can see this aura.
Then later Geordi fails to realize that another android built by the same guy who built Data isn't a human.
In this case, she was built with devices that mimic human life signs. It would stand to reason that they also shield any EM field emitted by the machinery. Otherwise, any old tricorder would be able to pick up the readings.
In Babylon 5 when Delenn and the White Stars take on the Drakh, the Drakh weapons systems glow brighter and brighter to build up the tension as they prepare to fire.
In Toku, a basic rule is "if you make your sword or foot glow, it will gain the power to explode rubber monsters."
Kamen Rider Faiz had an interesting spin on it: The five Riders' costumes were covered with "veins" through which pumped a glowing substance that to powered them. In nighttime scenes, the "veins" and visors would glow, and use of a Finishing Move would cause a bead of energy to run from the belt (the main power source) to the Rider's foot or sword or whatever they were going to use to kick butt.
After returning from Mt. Sinai after his first meeting with God, Moses was said to be glowing with beams of light emiting from his head. A mistranslation from Greek to Latin caused Donatello to sculpt him with horns.
In Dungeons & Dragons, the Wizard's hands and the party's weapons are shown glowing with power.
In Dungeons & Dragons third edition, magic weapons have a 30% chance of glowing with light equivalent to that of a torch.
In fourth edition, if you don't want to have a bunch of (potentially handy) secondary effects, you can get a Fire, Ice, Poison, etc. enchantment. Activating the enchantment changes your next attack into the specific element type, nothing more. Except the Sunblade enchantment, which gives radiant damage and illuminates a large area around the sword itself. Great for slaying undead and certain types of abominations; NOT so great for doing so stealthily. Oddly enough, there's only a total of about five or six weapon enchantments that will mechanically give off light, although flavor text varies wildly.
Exalted puts this principle to good use: the more Essence you draw into your Charms over a scene (i.e. the more powerful you make your superpowered attacks), the more glow, or Anima (in the parlance of the game), you produce. It begins with your Caste mark faintly appearing on your forehead, progresses into a glowing field or effect which physically envelopes you in various waysnote (brilliant golden glows for Solars, sickly green lights for Infernals, silver tattoos lighting up across Lunars' skin, elemental environmental effects for Dragon-Blooded, spiritual auras and halos for Sidereals, bleeding necrotic Essence for Abyssals, and industrial or technoscientific effects such as electric discharges and arcs, billowing steam, and even chemical or molten metal secretions from Alchemicals' skins), and culminates in your Anima Banner unfurling in some spectacular fashion. Once those Charms get about 16+ Essence pumped through them during a fight, a couple of battling Exalted can be seen unmistakably for miles around, and can even approximate daylight visibility conditions during the night.
Which might seem like a horrible disadvantage to the cause of stealth, except that an Exalted with 16+ Essence running through their Charms is more or less a Person of Mass Destruction at any rate, and not to be fucked with.
The player of Deus Ex gets a glowing nano sword. It is otherwise perfect for sneaky silent kills, but the bright glow tends to draw attention.
In World of Warcraft, enchanters can put a glow on any weapon. Typically, the more powerful enchants glow brighter, and the type of enchantment determines the color of the glow.
In the Burning Crusade expansion to WoW, Blizzard one-upped themselves by enabling enchanters to apply a glow to weapons that's actually a complex graphical animation. The Mongoose enchant causes your entire weapon to crackle with lighting, while the Savagery enchant makes your weapon drip blood.
While the primary theme of The Burning Crusade was "WoW IN SPACE!!!!", the secondary theme was "glowing stuff is really awesome". Seriously. Just look at most of the new areas - they're glow-tastic. Also, both of the new races have glowing eyes.
The multi-colored glowy-Lite Brite-Crystal cave in the original Un'Goro Crater was simply power-glow-tastic.
Wrath of the Lich King too, the whole nexus which is Malygos' lair is really one hell of a glow-tastic Scenery Porn.
In Cataclysm, Blizzard one-ups themselves again with the Power Torrent enchant, which shifts through the colors of the rainbow periodically and is the best-in-slot enchant for all raiding casters.
In Dragon Quest 8, Once a character reaches maximum tension, that character will glow until they attack or use magic that has a quantifiable effect, be it damage, healing or a stat buff. They'll also stop glowing if a boss nullifies their tension with a wave of ice.
In Final Fantasy, any place with a constant glow to it (such as the Mako Reactors in VII and Bahamut's hideout in VIII) is very important place with lots of either magical or technological power hidden from mortals. Party members tend to glow when using special abilities, and LimitBreaks always glow brightly.
An interesting example is in Final Fantasy VI, where Kefka is surrounded by a pyramid of magic before the final fight. In addition to showing his immense magical powers, it reflects his emotions: when he's taunting the party and laughing, it's blue, then turns purple as he laments the futility of life, green when the party members declare he's wrong, then red when he gets angry. Emotion Glows too.
City of Heroes (And Villains) doesn't shy from this, either. By hitting Level 30, characters gain the ability to attach an Aura of his choice to every costume. Most of these simply Glow (although some get creative and crumble instead), and none of them does anything other than being awesome.
Even without the lvl 30 auras, most melee characters have a set of glowy auras from a variety of defensive powers (and even being able to run fast causes your feet to glow)
In Fable, your tattoos and hands glow with high enough magic levels.
Later games in the series implement Full Synchro as an effect you can get in battle if you're skilled. It's depicted by Rock glowing (his color becomes light) and a pink halo spinning about his body. Very powerful NPCs and enemies in cutscenes also flash with light, notably Gospel in the second game, Proto (Alpha) in the third game and the Cyber Beasts in the sixth.
Every version of Mega Man who can charge up usually glows while doing so. Mega Man X was the first to glow different colors depending on how much he's charged. With the double-shot and Zero's Z-Saber in X3, he glows blue, yellow, pink, and finally green to indicate he can fire two fully-charged shots and the Z-Saber. Zero glows these same colors when he charges up his Z-Buster, but X3 is the last game where Zero can use his Buster the same way, and X one-ups him for once by launching an energy wave when he swings the Z-Saber, assuming he has the double-shot.
Early Mega Man games had Mega Man get Power Glows when charging the Mega Buster. Because of the way NES graphics worked, the powerups scattered around levels would exhibit the same pattern in time with his. Later games added Sucking-In Lines.
Omega Zero has a white aura around him, so you know he's not to be taken lightly.
This was carried over from Virus Infected Zero in X5, who was surrounded by a ominous purple aura.
Oblivion manages to pull this off much better, with enchanted items having a slight subtle glow instead the plastic-wrap one. Mods exist for both games that remove the effects if you don't like them.
Skyrim mixes the two: enchanted weapons have faintly glowing swirls and whorls like Morrowind (only way better-textured), while armor and jewelry uses the Oblivion glowy outline.
The Dragonborn expansion for Skyrim introduces the Dragon Aspect Shout, which surrounds the user with a set of glowing, draconic armor.
The old Magic Knight game Spellbound for the ZX Spectrum featured the spell Armouris Photonicus, which if cast in the right place would make your armour glow sufficiently to traverse two darkened rooms safely, making this Older Than The Nes.
Zork: "Your sword is blowing glue! Wait, let me try that again."
Dragon Ball Z: Budokai Tenkaichi 2: low-ranking characters might glow faintly when summoning ki; high-ranking characters glow with intense brightness at all times, and even the simplest moves look like a fireworks display crashing into a laser light show.
Kingdom Hearts. And Kingdom Hearts II is even worse. Everything sparkles, lights, shines, flares, an so on... MY EYES!!
Custom Robo: Soulboost causes this, although the best the graphics engine could do with it is turn the robo's model gold.
Mass Effect's biotics have glowing energy about them when they use their biotic powers, especially when using a powerful biotic move. Samara is a really good example, especially when she fights her daughter Morinth to the death.
Element Zero, though rarely seen directly, apparently has quite an energetic glow about it. This makes perfect sense when you consider that it actually constitutes exotic matter under certain conditions.
The Soar Star in Super Mario Galaxy gives Mario a white glow around his hands, along with a pair of red trails as he flies along.
Many MMORPGs have weapons that glow when they're enhanced. So what does a newbie typically ask of the wielder of such a weapon?
"What kind of weapon is that?" Nope.
"Where did you get that?" Not even close.
"How do you make your weapon glow?" Bingo!
Fly FF took this Up to Eleven— every piece of equipment could be upgraded... and L10 Enhancements created awesome blue glows. If you had Level 120 Equipment with L10 Enhancements in every slot, you got glowing blue wings as well as a pulsing blue Battle Aura. That said, you had to be very rich to obtain that gear.
Inverted in Phantasy Star Online. The common, weak weapons are all photon based, as opposed to some rare, high end weapons, which are non glowing real guns and swords. presumably because photon based weapons are cheaper to make than a properly tempered steel katana or a finely machined kinetic firearm.
Rachel is surrounded by an ominous purple glow when in her Unlimited mode.
In Metroid Prime, anything even vaguely related to phazon is always glowing. In the rest of the series, all powerups glow.
In Team Fortress 2, critical projectiles glow your team's color, as do weapons when under an effect that will give them crits. In addition, an Ubercharge makes you glow your team's color while giving you invincibility for ten seconds.
While not exactly a glow, the "unusual" hats give off a special aura when worn.
In the Fallout series there is a type of ghoul called Glowing Ones. As their name suggests, they are brightly glowing ghouls. They are a stronger type of the regular ghoul with special powers directly related to their heavy irradiation, including a burst attack where the entire area around them briefly becomes irradiated, too.
Dynasty Warriors: Strikeforce. All characters glow when they enter their Super Mode.
All enchanted weapons in Dark Messiah glow in their enchantment's respective color. Escpecially lightning-enchanted weapons glow so bright that in dim lighting conditions it becomes hard for the player to see anything else (such as enemies, for example...).
In the online game Bearbarians, warriors who begin to rack up a combo damage bonus begin to glow, unless you've turned off particles.
Playstation All Stars Battle Royale uses this effect to distinguish "All-Star Power" (AP) both in-game and in-story, where the winner in each character ending can be seen glowing with Blue (having defeated Polygon Man, the apparent source of AP). Characters will glow slightly when able to use a Level 1 Super, become brighter at Level 2 and be almost completely illuminated when using their Level 3.
Magic items glow in Goblins when being used. Some of them also "smoke" light.
Actually they channel the users aura, which changes color and effect (i.e., "smoking" light) depending on the individual. This is why when someone loots a magic weapon, it glows differently than whoever was just using it.
Whateley Universe example: Tennyo's sword glows a brilliant blue, and can cut through pretty much anything since it's made of some sort of anti-matter. Tennyo herself does the glowy bit when she gets really amped up, complete with Red Eyes, Take Warning. Several Energizers like Golden Girl also do the full-body glow when they kick in their powers.
Unlikely Eden example: Heather's axe starts of as just strangely blurry, but later, as her Preferred Weapon Effect kicks in it attains full glow. Additionally, the eyes of all Coalition soldiers and Ourkind bioluminesce when their abilities are activated.
In Spectral Shadows we have Christine with her healing powers and her fur glows yellow when in use.
In Phaeton this happens when Trayen energises, Teliha levitates and when Sam shapeshifts, there are probably other powers that do this too but it just hasn't been mentioned yet.
In Beast Wars, Sparks glow, which makes sense because they are powerful. So do many of the things belonging to the aliens.
In some of the BIONICLE movies, the characters' masks glow while being used.
In the earlier episodes of Kim Possible, Shego had clawed gloves that glowed with a green light when she fought; the glow was implied to amplify the force of her attacks. In the second season, she began displaying the ability to use the glow as a projectile attack, throwing blasts of energy, and it was retconned into a superpower called the "Go Team Glow", which she and her brothers obtained as children when they were exposed to an alien meteorite.
My Little Pony: Friendship Is Magic applies this to, well, magic, which arguably qualifies as this trope. In the premieres of both the first and second seasons, for example, Twilight's eyes (and the second time, those of her friends too) glow when she and her friends unleash their Care Bear Stare.
Also happens in her exam flashback in "The Cutiemark Chronicles" when the Sonic Rainboom triggers her innate magic and makes it go out of control. Complete with Power Floats and a few (thankfully temporary) cases of Baleful Polymorph of bystanders.
During Twilight's transformation into an alicorn she gets surrounded by a bright purple light in the shape of her cutie-mark. Earlier in the episode, that very same power glows makes it look as if it burned Twilight into a pile of ash, much to her friends' terror.
Sealab 2021: "You see this, you see how my body's glowing like that? Yeah, a lot of people can't do that."
In The Secret Saturdays, the human members of the titular Saturday family each have a weapon with some sort of glow, and then Zak's eyes glow when he uses his powers.
Light is a form of energy, and flow of energy is power. Light cannot be created from nothing, so power is required to make anything glow, even a tiny LED.
Incandescence is what causes really hot things things to glow, and hotter things to glow more. It is the underpinning of this trope, and it's cultural ubiquity comes from the two most primal sources of glowing power: the sun and fire. Both glow with incandescence. Light bulbs, lava and molten metal get an honorable mention.
Lightning glows by a slightly different way, wherein the electricity ionizes the air. But like incandescence, the light is emitted by an electron dropping back to a stable position.
Averted when electricity travels through a wire. Invoked by this USB cable, which "visibly shows the electrical current" (if you're in a dark room that is).
Unlike the ones in TV, real nuclear reactors glow blue. Pretty, but for the record, if you see Cherenkov radiation in air, you have basically several minutes left to live.
If what's separating you from the core is not air but water, you're probably fine at only a few meters away. Pool-type research reactors (used for irradiating stuff for various reasons, not for generating power) are basically deep swimming pools with the core at the bottom, and it's often possible to look directly at the core (through ten meters or so of water) and actually see the Cerenkov radiation.
The popular idea of green radioactivity dates back to radium paint, which was used for clock dials and glow-in-the-dark signs in 1920s. Later when the hazardous effects of radiation were discovered, the green glow got its new meaning. Oxidising white phosphorus, also quite nasty material, glows green too.
It's worth making a distinction here: radium does not normally glow. Mix it with a phosphorescent or fluorescent material, though ... the particular one used for watch dials etc. glowed green, and so in the popular imagination, all radioactive materials glow green.
Tritium, a hydrogen isotope, has replaced radium in all applications of Real LifePower Glow. It is still radioactive, but emits relatively harmless beta particles, turning into helium-3.
The tritium isn't glowing in itself - so you put it into a glass vial covered with phosphorus, and it's the phosphorus that's glowing because it's reacting to the beta radiation. Depending on the chemical composition of the phosphor (not the element, but a term meaning substance that glows when energetically excited), you can get different colors. It's a self-powered fluorescent light.
Another is that the presence of uranium or uranium compounds during the production process can turn glass and diamonds yellow-green or green (with higher uranium concentrations making the color more brilliant green), which then glow under a black light.
MSNW, a company building a fusion rocket engine, has some photos on their webpage of some things that are ostensibly fusion or plasma related glowing nicely.