In the Whateley Universe, Golden Girl fits this trope. She's another student at the Super Hero School Whateley Academy. She is strikingly lovely, and when she uses her powers (golden energy blasts, golden force fields, super-strength, flight), she's covered in a golden glow. She actively hates Phase (one of the main characters and good guys) and tries to hurt her every time they spar in aikido.
The main character's turn towards genuine evil is marked by the song "Brand New Day":
"It's a brand new day
And the sun is high
All the birds are singing
That you're gonna die!"
Dr. Horrible, the supervillain, wears white (at least at first), and Captain Hammer, the Designated Hero, wears black.
In The Salvation War, the angels OF Heaven are portrayed as the masters of light. This being The Salvation War, the angels are very much not on the side of good.
And just to put the cap on it, the archangel Uriel is eventually killed by a laser beam. In other words, by pure light.
The famous ''Rocks Fall, Everyone Dies'' YouTube pop saga by Jittery Dragon somewhat invokes this trope at its fifth alternative ending, with Pterano, by touching the coldfire stone, becoming an angel; cue the ominous orange light surrounding him, actually a mixture of edited footage from Land Before Time X with footage from Neon Genesis Evangelion. This became a running gag within the series, having him reappearing in the second part of The land before everyone froze to death, stating that he is the cause of the climate change as he came on the Great Valley.
Most of the villains in Red vs. Blue have much lighter armor than the "heroes"
Meta and Wyoming both have white armor.
Agent South, while not evil, is certainly not a good or nice character, especially not compared to her brother Agent North, who wears similarly-colored, but darker, armor.
Carolina has bright blue armor, and is at best scarily effective, at worst vindictive and crazy.
Wash, when he's not being Dark Is Not Evil,. He even has yellow trim, one of the happier colors of the electromagnetic spectrum.
Most of these are exacerbated by the fact that they fight Tex at one point or another, who wears the darkest armor in the series.
Freelancer mooks wear white armor, as do some of the UNSC/separatist troopers - who admittedly might not be evil, but they're shooting at our favorite characters, so we're rooting for them to get heavily owned.
The plot for Off Switch has the hero fighting to save his world (which is composed of shadows) from the invading light demons.
SCP-1591, the "Fallen Star." Its light can disintegrate all matter.
In the Creepy Pasta "Thanks", the protagonist's nightlight allows a monster to find him/her. The monster mockingly thanks him/her, claiming it couldn't find him/her in the dark.
Worm has Purity, a parahuman with the power to project incredibly powerful hard light attacks and who can level city blocks with light. She also happens to be a Neo-Nazi.
In Phaeton Light is the most destructive and corrupting of all elements, people with light based abilities tend to go mad really fast
Night Vale's neighboring town and rival, Desert Bluffs, is made out to be a happy place, much more upbeat than the defeatist and Orwellian Night Vale. Its radio announcer Kevin constantly rambles about how nice it is to live there, and even its cover art is bright yellow with a big sun prominently featured, in contrast to Night Vale's dark purple and ever-watching eye...and then Cecil describes the blood on the walls...
Specifically, Desert Bluffs has been taken over by a company called 'Strex Corp', which seems to be more of a malevolent, multidimensional force taking the form of a giant company. In another plane of existence, it's form is a bright light, and is described thusly;
The light is alive. And malicious. And vast. And encroaching. It buzzes and shines and everything about it hurts those that are close to it, and destroys those who are within it.