Angemon and Angewomon of Digimon Adventure are both angelic Digimon with golden hair who both debuted to promptly easily defeat a powerful dark Digimon with their powers of light. Angewomon takes this almost to ridiculous extremes - her partner is Hikari Yagami, whose first name translates to "''light''", and who uses the Crest of Light to make her evolve to Angewomon to begin with. Oh, and near the end of Adventure she started glowing.
That said, aside from the homunculus, the overwhelming majority of the villains invoke Light Is Not Good, and the only characters with anything resembling light powers are both villains.
Except for the Colonel, who has light-themed powers and is most definitely on the heroic side.
Though transforming tends to make them look more threatening in Dragon Ball Z, all the Super Saiyans, apart from the movie villain Broly, embody this with a golden hair and aura, even Vegeta by the end of the series.
In Legend Of The Guardians The Owls Of Ga Hoole, Boron and Barran, the two leaders of the Guardians use golden helmets and have a white plumage. Though considering they're snowy owls, it's not like they have much choice regarding their feather colour, and the villains are also the generally light coloured barn owls.
In Tangled, Rapunzel, a gentle, caring girl who is a Friend to All Living Things, loves daylight (as well as starlight) and has shining golden hair because her mother ingested a flower that had grown from a drop of liquid sunlight.
Being the benevolent overseer of the candles of life, the Candlemaker from The Book Of Life, is this.
Films — Live-Action
The Light Side in Star Wars. The Expanded Universe is a bit more relaxed with this, though. Oddly enough, nobody ever calls it the "Light Side" in the original trilogy (and not in the prequels either)... it's only ever "The Force" and "The Dark Side of the Force." The entire idea of calling it the "Light Side of the Force" most likely came from fans making the "Dark Is Evil = Light is Good" connection on their own!
Tangina: When people die, there's a wonderful light as bright as the sun. But it doesn't hurt to look into it. All the answers to all the questions that you ever want to know are inside that light. And when you walk to it, you become a part of it forever.
In the first The Lord of the Rings film, Arwen appears to Frodo in a flowing white gown with light radiating out from her. This is just a vision to Frodo but it symbolises that she is good and is there to help him. Though she does warn him that she could end up evil and remain like she is.
A bit of a no-brainer but the stars in Stardust. They shine when their hearts are full of joy and happiness although Yvaine actually uses this as a weapon against the witches.
Played straight in one of the very last scenes of Pans Labyrinth, which shows the throne room from King & Queen of the Underworld as a golden place full of bright light, where Ofelia is received after she dies in the real world.
Night Watch's Light Others live and breathe this trope... though, it can be said that the series examines this trope, bends it, reshapes it, subverts it, averts it, and when all else is lost, the author throws in the towel and pretty much says that all bets are off.
In The Dresden Files, sunlight is anathema to most creatures of the Nevernever, and can disrupt more negative and evil enchantments and spells. Also, the Swords of the Cross emit light that cancels out the powers of the Denarians.
Plus the Summer Faeries tend to be fairly benevolent whereas the Winter ones are actively sadistic, although both sides are manipulative and capable of great crimes, when you put the two Courts next to one another it is played fairly straight
The Armor of Light by Melissa Scott and Lisa A. Barnett.
In Robert A. Heinlein's Magic, Inc., the heroes storm Hell because light always overcomes darkness (since darkness is merely the absence of light), and they are the forces of Light, so it does not behoove them to sit around reacting to the demonic forcs.
Diane Duane's Young Wizards series works with this considerably, especially in the first book, although they play with it increasingly through the series and at the end of the third book have a decisive Redemption arc where it is shown that Dark Does Not Have To Be Bad. Of course, the fact that the Powers don't live within linear time means there are still loads and loads of incarnations of the Lone One running around being evil for books and books more, but they've finally given him the chance to start going home.
how chang'd From him, who in the happy Realms of Light Cloth'd with transcendent brightnes didst outshine Myriads though bright
The default in The Lord of the Rings and J. R. R. Tolkien's other words, though there's more subtlety to it than that: the Elves are associated with the cold light of the stars and later the moon, while Men are associated with the hotter, harsher light of the Sun. Tom Bombadil also notes that he remembers when 'the dark under the stars was fearless, before the Dark Lord came from Outside', so Dark is not intrinsically evil.
In Jennifer Crusie's Maybe This Time, Andie urges ghosts to Go Into the Light, assuring them that it's probably good, because light is.
In the land of Caederan, Light is one of the two "supra-elements" that surround and infuse the four elemental magics. Each element has a light aspect, which is the proper and natural use of that element. In addition, it is possible for someone to turn you into an orah, those who "live aligned with light alone," and can access the light side of each of the four elemental magics. It's mentioned specifically that fire called by an orah burns hotter and cleaner, and is much easier to prevent from running amok, as compared to fire called by an aesh.
Manichaean scripture spread the idea of light being good and darkness being evil, which is likely why it sometimes shows up in mainstream Christian rhetoric despite the Bible not favoring either (as in the cases of Milcom, Satan and Lucifer being bad and the shade of the lord good). However, their are many a passage in canon Christian scripture that can be taken this way if not put against the work as a whole.
I John 1:7—>But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all sin.
Job 33:28—>He redeemed my soul from going down to the pit, and I will live to enjoy the light.'
Psalm 18:28—>You, O LORD, keep my lamp burning; my God turns my darkness into light.
Isaiah 50:10—>Let him who walks in the dark, who has no light, trust in the name of the LORD and rely on his God.
John 1:4-5—> In him was life, and that life was the light of men. The light shines in the darkness, but the darkness has not understood it.
Romans 13:12—>The night is nearly over; the day is almost here. So let us put aside the deeds of darkness and put on the armor of light.
Exalted gives us The Unconquered Sun, the divine embodiment of virtue and righteousness, created by the Primordial of dickery solely because he wanted to find out what would give him purpose. And boy, did he succeed there, as the Unconquered Sun saw that the Primordials were yoking Creation about and helped lead the struggle to overthrow them. His chosen, the Solar Exalted, are supposed to be like this... save for that little Great Curse thing.
Prior to the 4th edition, where they could be good or evil, angels and metallic dragons, who will actively attempt to aid weaker races. The 4th edition still played this straight with the good dragon god Bahamut.
The white color in Magic: The Gathering uses a sun for its symbol. It has by far the lion's share of cards concerning healing, protection, spells that disarm creatures or only destroy/remove creatures when they attack you, and creatures traditionally associated with good such as angels, knights in shining armor and honest soldiers. Depending on the block, white cards can just as easily make for Light Is Not Good, however.
In terms of characters wielding White Magic, the most famous are heroic, but there's a sufficiently large amount of paranoid Knight Templars as well. So light is pretty much neutral in this setting.
Both subverted and played straight with the Living Saints of Warhammer 40,000. They are shining examples of all that's good about humanity, avatars of the Immortal God-Emperor of Mankind, shining with light that causes most heretics to repent and desire to serve the Imperium, that fills the hearts of the faithful with unshakable courage and joy in serving the Emperor. Within the Imperium, almost universally accepted as unambiguously morally good, serving humanity selflessly in and out of combat and eventually sacrificing their lives for the good of the Imperium. Outside the Imperium, they're probably viewed no better than any other Imperial tool.
The Stellaknight archetypes' appearance and implied role in the Yu-Gi-Oh! OCG saga started in The Duelist Advent implies that they are benevolent or even heroic.
This trope is sprinkled liberally throughout the games as a whole. Many of the climatic scenes involving Link use dramatic lighting to grand effect - just watch any of the Master Sword sequences. Probably most prominently displayed thematically in The Legend of Zelda: A Link to the Past, where Ganondorf's dark power has corrupted the Sacred Realm (a Golden Land where the Triforce once resided) and turned it into the dangerous and evil Dark World. Subverted somewhat in Twilight Princess.
Amaterasu, the goddess of the sun and mother of all life, in Ōkami.
Homestuck: The White carapaces are all the good-guys. Rose plays with this, as she is the only light player to not fall into Light Is Not Good, but she's also the one most involved in darkness and destruction, though she never raises a hand to her friends and always fights with them. She becomes a more traditional example after her ascension to God Tier (featuring bright orange robes), and later when she's shown to use the Quills of Echidna.
In Aelan mythology from Ustal Naror islands, good beings learn to shine.
Stella from Winx Club gets her powers from the Sun (well, and the Moon, but mostly the Sun), and most of her attacks consist in casting beams of light. Despite her occasional selfishness, she cares a lot about her friends.
In BIONICLE, every sentient character has a dark side and light side, representing of course good and evil. These could be tapped into, to obtain either light or shadow powers, and naturally, shadow is easier to master, and makes one corrupt. To those who have light or shadow powers from the get-go, obtaining the opposite "element" can prove difficult, since the two powers tend to cancel each other out. This is a mostly late development, however. While bad guys were since early associated with darkness, the light in Bionicle was originally more ambiguous and meant to be "special" rather than "good".