Also interesting is Section XIII's Badass Creed, which we hear when they show up in force. In it, they self-identify as God's assassins, violating all of the Church's Commandments in the name of Judas Iscariot in the hope both of furthering the Church's cause and damning their souls as a way of passing on to and invading Hell. They're still probably paladins in comparison to the rest of the Church's militant orders... which says something about those.
The Royal Knights of the wider Digimon canon are this, an order of immensely powerful knight Digimon convened to serve the god of the Digital World (whoever that may be in that particular universe); the order was founded by, appropriately enough, ImperialdramonPaladinMode. All members of the Royal Knights are very different from each other and have very different sets of powers, so they fit the related powers tendency only to varying degrees. The most prominent members of the order include Omegamon, Magnamon, Dukemon, Dynasmon and LordKnightmon.
Comic Books
Priam Agrivar from DC's Advanced Dungeons & Dragons and Forgotten Realms titles back in the 80s, one of the better fleshed-out examples of the classic D&D-style (AD&D 2nd Edition in particular) paladin — complete with all-too-human failings (like lingering alcoholism) and doubts but ultimately the determination to prove himself worthy as well. Interestingly, he seems to owe formal allegiance to no specific faith or other organization, or if he does, it's never shown; he always appears as essentially his own man trying to do good as best he understands it, and his powers seem to work well enough regardless.
Fan Works
Balian of Ibelin in the Chance Encounter series pretty much is this trope. Considering one of his nicknames is "The Perfect Knight" and going down to hell to fight the Devil for the soul of his dead wife (while he does get smashed around by Satan with ease, he is assisted by the recently canonized by the Archangel Gabriel Prince Hector of Troy. Yes it is very strange) this is hardly surprising. He is also something of a Woobie, as it is pretty much guaranteed that he will be maimed at least once every 4-6 chapters. As well as being possessed by a dark version of himself.
In Allronix's TinMan fanfic, the Tin Men themselves are of this trope, created by Empress Dorothy to honor the original Tin Man, Nick Chopper, sworn to serve and protect the citizens of Oz "from the greatest monarch to the smallest insect."
TRON: Alan hadn't intended to create a de-facto holy warrior who fights for the oppressed User-believers, but his creation turned out that way. Too bad about the sequel...
The Knights of the Cross in The Dresden Files are basically paladins, complete with holy swords, a Mission from God, and plate armor. Especially Michael. Of course, some of them pack more modern gear and weapons, like Sanya, who carriers a Kalashnikov. They're also notable for being one of the most positive portrayals of paladins in all of fiction, being good, honest, kind-hearted men who don't force their beliefs on others and help anyone who truly needs it.
The Church Knights from The Elenium by David Eddings are basically Paladins, though it can be hard to see through their worldly tarnish on the Pandion, Genidian and Alcione knights. Cyrinic Knights are closest to the ideal, being the most religious and having shiny armour to boot. The manner of their Preceptor Abriel's death — charging a 300+ foot monster — is very Paladin.
The Knights of Solomnia are the closest equivalent in Dragonlance and their Dungeons and Dragons tie-ins provide rules that essentially make this character a paladin equivalent (though there are different orders with different emphases in terms up fighting skill, leadership and divine power).
The protagonists of Domina are referred to as Paladins, specifically because it seems like it will "sell." Derek is closest in powerset; he's The Hero and a Barrier Warrior.
Live-Action TV
Have Gun — Will Travel was an American western television series that ran from 1957 to 1963, starring Richard Boone as Paladin, a gentleman gunfighter and West Point educated former army officer who worked as a "fixer" of sorts, settling disputes and solving problems that would normally escalate into unnecessary violence.
Alluded to/played within an episode of Bones, where Booth rescues a young boy by gaining his trust with his family code word, which happens to be "Paladin". Booth is sort of a Paladin, only without magic powers.
Angel could be said to be this, on Angel, despite his unholy vampire nature. His mission is frequently said to be "helping the helpless".
Pathfinder, as a continuation of the d20 System D&D line, also has the classic paladins. They're a bit beefed-up compared to what they were in 3.5.
Paladins in the 4th Edition of Dungeons & Dragons do not follow the Always Lawful Good restriction: instead, Paladins are servants of any god, and they follow the tenets laid forth by that god rather than follow an alignment. Paladins in the Essentials line for 4th Edition choose a Virtue (such as Sacrifice and Valor) and have options within that virtue (though Sacrifice Paladins fit the usual Always Lawful Good bill).
Pretty much all additions of Dungeons & Dragons also have an inversion of the paladin trope; some variation of an "anti-paladin", a mirror image of the paladin that replaces "good" with "evil" and "holy" with "unholy". 3e had a Prestige Class called the Blackguard (which could include fallen paladins) as well as the Paladin of Tyranny (Lawful Evil) and the Paladin of Slaughter (Chaotic Evil). Pathfinder went back to using straight anti-paladins, and 4th edition makes the issue moot by allowing your paladin to be dedicated to any extreme alignment.
The Space Marines in general arguably have this flavour if seen sympathetically, with their existence being militaristic and fighting in the most important warzones where needed, and generally their devotion to the cause of the Emperor and the Imperium (and by that extent, humanity in general) is encouraged to border on religious fanaticism (though also generally just off the mark from religion). Played dead straight by the Salamanders chapter, who are especially protective of Imperium citizens whenever the Salamanders see them, have their own chapter-personal cult which extols the values of self-reliance, loyalty and self-sacrifice, and mostly utilize flame weapons and Thunder Hammers — fire and hammers being fairly common iconography of The Paladin.
As the military arm of the Ecclesiarchy (the Imperial state church), the Sisters Of Battle also fit this role.
In Rifts there are a lot of people that seem like paladins, but the real deal comes from the Wormwood supplement in the form of the Apok, whose literal class description is incorruptibility. They get absolute immunity to all manner of effects, but in classic Rifts style, they look like demon hobos. Also interesting because they are required to have been evil and truly repented, rather than being good from the start.
Dawn and Zenith caste Solar Exalted tend to put on a lot of the trappings of this trope, such as holy light and golden armour...as for how well they actually embody it, that's a matter of individual choice and the nature of one's LimitBreak.
The Fighter/Knight class in the original Final Fantasy plays closer to a paladin than a true knight, as once the Fighter class is upgraded to a Knight they have the ability to use low-level White Magic.
Cecil in Final Fantasy IV, once he casts off his Dark Knight mantle. Also a Lightning Bruiser barring offensive magic. The DS remake makes him even more of a tank, with the (passive!) ability to draw attacks to him and counter.
The Paladin class is used by human units in Final Fantasy Tactics Advance and Final Fantasy Tactics A 2. The class has two abilities that dish out Holy damage to enemies, but the rest of the skills involve healing allies of injuries and ailments, protecting them from enemy attacks, and convincing enemies to leave the battle. It is worth noting that the title "Paladin" only seems to describe the general skillset of the class, and not the personality, as there are at least a couple of missions in Final Fantasy Tactics Advance in which you fight a bad guy whose job is Paladin.
Warcraft paladins are the Trope Codifier for good but not Lawful Good paladins that follow "the Light" instead of a specific deity. They also tend to retain their powers as long as they think they're doing good, which can lead to some unpleasantthings. Originally, they were members of The Order of the Silver Hand, until said order got decimated after the fall of Lordaeron. They later served the Argent Crusade, and their respective factions, the Alliance or Horde in general.
The Warcraft III paladins were defensive/supportive hero units which supported their allies through healing, and armor-boosting aura, and a mass resurrection ability. They also had the ability to personally become completely invincible for short periods of time and their healing spell could heavily damage enemy undead units and most demons.
The World of Warcraft paladin is a melee class with healing and auras, with specs that allow them to be a dedicated shield-bearing guardian type (Protection), a Combat Medic (Holy), or a more light-focused Magic Knight (Retribution). The class is available to humans, dwarves, blood elves, and — as of Cataclysm — any race with hooves and a tail.
The Paladins of Battle for Wesnoth are Warrior Monk types who, like the White Mages of the setting, serve the philosophy of good itself, with no religious connotations. They start out as regular Horsemen who later level-up to Knights, and can then choose to either maximize their combat power by becoming Grand Knights or to acquire basic healing skills and Smite Evil abilities to become Paladins. While they are not as strong in melee as the Grand Knights, and not as good healers as White Mages, they are fast, can still very hard with their lance charges, and have 'arcane' anti-magic damage and resistances that make them very good at fighting the undead.
The Paladin tank of Command And Conquer Generals has the personality (no surprise considering that the USA faction is Lawful Good in this game) and has the ability to tank missile shots with a defensive laser.
The Paladin class in Dragon Quest IX plays like a typical paladin would. Is one of the more infamous game breakers especially against mage boss fights.
Baldur's Gate: You can take Ajantis into your party, but given the games limited NPC interactions, he doesn't have anything to say.
Baldur's Gate II: There's Keldorn and the Order of the Radiant Heart. There are also a group of fallen paladins who got kicked out of the order and are now common criminals. Meanwhile, Mazzy Fentan can't be a paladin because the second edition rules didn't allow it for halflings yet... but she's a Lawful Good, knightly servant of her deity who gives her special powers, so basically it's just a matter of terminology and minor differences in special abilities, and of her being bothered that she's not official.
Neverwinter Nights: Aribeth is one of the major NPCs in the game. And becomes an Anti-Paladin halfway through the story.
Neverwinter Nights 2 (though actually developed by Obsidian): Casavir stands out from most paladins by placing a much higher emphasis on Good instead of Order. When his superiors and fellow knights were unwilling to take action, he left and became the leader of a guerilla vigilante band that fights marauding orcs.
Knights Of The Old Republic: Being a Star Wars game, it has a lot of Jedi, which are pretty much Space Paladins. And like in Neverwinter Nights, poster girl jedi Bastilla will fall to the Dark Side, but can be saved.
Dragon Age has the Grey Wardens, who are very paladin-like in flavor, but aren't locked into any given mechanical build. Also of note are the Templars, who have a bit of paladin feel (hunting down demons and errant, usually evil mages) but who invoke Good Is Not Nice due to the game's Crapsack World. However, Templars are rather un-paladin-y in that they're sadly prone to becoming Knight Templars and running into Light is Not Good. Alistair, being both a Grey Warden and an ex-Templar with tank combat abilities, anti-magic, and (eventually) Smite Evil, is the game's best example of the trope; he manages to combine Light, Good, and (mostly) Nice, though he's certainly willing to Shoot the Dog.
Flynn in Tales Of Vesperia (especially the PS3 version) is the first true paladin style character in the series.
In Ground Control, Paladin is a title given to any Order of the New Dawn general who is permitted to act with autonomy. The Paladin Magnus is one, and despite not having any divine personal powers, he does have an arsenal of Order troops, aerodynes and hoverdynes at his disposal, and has the personality of a paladin, always choosing the 'good' option over the lawful.
's home), Anshar (Rohoph's home), and several other planets.]]. He is devastating against the undead, but is insufferable if you allow him to get on the subject of Yalortism.
The Paladins in Quest for Glory differ from the standard version trope in that they are openly Neutral Good from the start; the Paladin mentor Rakeesh defied the rule of law in his homeland because he thought it was narrow-minded and would only cause a needless war. The Paladin class is unlocked at the end of Quest for Glory II if you finish the game with high enough Honor, and is effectively a Fighter with nice bonuses like Healing Hands, protection from evil, and a danger sense, plus some optional quests that go above and beyond the main plot.
Artix Von Krieger from Adventure Quest, Dragon Fable and other games of the same company subverts the concept. He has a compulsive need to smite any undead creatures he comes across, and Adventure Quest Worlds reveals that Artix is the Champion of Darkness, and as such cannot use the light-based magic of a Paladin. Instead, he was trained in the ways of the Undead Slayer, whose power and purpose is to free the souls of those enslaved by undeath.
Paladin is also an available class in pretty much any Artix Entertainment fantasy game, though at least one version is member only.
In Rift, paladin is a warrior "defensive soul" with some White Magic abilities. While Amardis Mathos (the original in-universe paladin) certainly fit the usual profile, it's implied that not every paladin does.
The Paladin class of the Fire Emblem series is, for the most part, this In Name Only; it has nothing to do with holy warriors and cannot use any sort of magic beyond that afforded by magicweapons. Members of the class (allied ones, anyway) are generally upstanding, moral, and loyal knights, but are not holy by any means. The exception is the Jugdral canon, wherein the female variant of Paladins can wield healing staves.
There is a Paladin class in the Ultima series (at least until the later games where it gets merged into Fighter), which is the class associated with the virtue of Honor. But the Avatar himself also fits most of the criteria for the Paladin trope, and is the page image.
Goblins also has paladins of various roles. Most of them tend toward Lawful Good or Lawful Stupid, but one of them, the infamous dwarven paladin Kore, is one of the most evil characters of the series, despite having the full range of paladin powers available to him. Big-Ears, by contrast, is a perfect reconstruction of the trope; he chose his class to defend the weak and is prone to Tender Tears.
The Trope Namer is, of course, the actual Paladins: the "Twelve Peers", the foremost Christian warriors of the court of Charlemagne; they were first described in The Song of Roland, and the eponymous Roland was said to have eventually become the leader of the Paladins. What they actually did, and what was merely propaganda and hearsay, is a little less clear.