Freudian Trio/Web Comics

Examples of s in include:

Twice Blessed

 * Cade Masters - the swashbuckling womanizer (Id)
 * Vadim Valntipur - the level-headed old dwarf (Ego)
 * Melchior - the brainer-than-thou mage (Superego)

Arthur, King of Time and Space
Which also contains an explicit lampshading here Interestingly, this is almost certainly a homage to Star Trek, at least in the space arc, where Guenevere is the ship's doctor and Arthur, as king, is effectively captain of the Excalibur.
 * Arthur - The laid-back leader who mediates between the other two (Ego)
 * Lancelot - ultra-moral and perfectionistic (Superego)
 * Guenevere - confident, determined, and potentially a source of friction (Id)

Fletcher Apts

 * Bob: Straight Man Hamster (Ego, tending toward Superego at times)
 * Doug: Hollywood Nerd Dog (Superego)
 * Bill: Boisterous Bruiser Goat (Id)

Gunnerkrigg Court

 * Coyote (Ego)
 * Reynardine (Superego)
 * Ysengrin (Id)

Lagend

 * Nikol Mimagi(Ego)
 * Lewk (Id)
 * Serra Serif (Superego)

The Order of the Stick

 * The trio left in Azure City when the Order was split up:
 * Celia: Stupid Good Actual Pacifist, out of place in an adventuring party (superego)
 * Belkar: Stupid Evil Heroic Sociopath, increasingly The Millstone (until he suddenly wasn't anymore) (id)
 * Haley: Pragmatic, Chaotic Goodish, has to deal with the mistakes made by the above two along with everything else (ego)
 * The trio that escaped with the Azurite Fleet:
 * Durkon (Superego; rational, focused on their long term goal.)
 * Elan (Ego; listens to everyone's point of view)
 * V (Id; focused on his/her own immediate emotional needs [to be the one who saves everyone]. A rare example of a superintelligent id)

Penny Arcade
Prior to the series's beginning, there was a third roomate, Jim, who apparently filled this out for the main characters:
 * Tycho: Intelligent and snarky (Superego)
 * Gabe: Emotional and dimwitted (Id)
 * Jim: "Even-handed, and slow to anger" (Ego)

Problem Sleuth

 * Problem Sleuth: charismatic, a born leader, balanced (Ego)
 * Ace Dick: brash, gluttonous, violent (Id)
 * Pickle Inspector: highly intelligent (Superego)

Homestuck
Homestuck has a "Trio plus one", complete with psychological reasoning:
 * John: Ego
 * Rose: Id
 * Dave: Superego
 * Jade: Unconscious Mind

Something*Positive

 * Aubrey: Brash, impulsive, confrontational, slightly sociopathic (id).
 * Davan: Somewhat of a Jerkass, but much more self-controlled than Aubrey (ego).
 * Pee-Jee: Moral (relatively), often the voice of reason (superego).

Slightly Damned

 * Kieri is calm and thoughtful most of the time: Superego (but develops tendencies in the other two types)
 * Buwaro is naive and impulsive: Id
 * Rhea keeps the other two under control: Ego

The Adventures of Wiglaf and Mordred

 * Mordred: self-centered, lazy, and generally only moving if there's something in it for him, often amusement (Id)
 * Wiglaf: the self described "perfect hero," and the one with an emotional need to help people (Superego)
 * Driver: does most of the explanations and lampshading, the laid-back rather than lazy one (Ego)

Narbonic

 * Mell: focused on violence and BFGs (Id)
 * Dave: the worker bee who has the tech skills (Superego)
 * Helen: the Mad Scientist who is their boss (Ego)

Skin Horse

 * UNITY: the violence-oriented zombie (Id)
 * Tip: the psychiatrist who tries to talk things out (Superego)
 * Sweetheart: the genetically-engineered superdog who is the usual team leader (Ego)

Hanna Is Not a Boy's Name

 * Hanna: Emotional but smarter than he seems, a leader, practical (Ego)
 * ...: Nigh emotionless, always cool, taking necessary action and pointing things out (Superego)
 * Conrad: Short-tempered, blustery, often does not think things through (Id)

Scandinavia and The World

 * Denmark: Fun-loving party boy (Id)
 * Sweden: Logically-minded to a fault (Superego)
 * Norway: Friendly camping hobbyist (Ego)

Jerkcity

 * Pants: Excessively vulgar weirdo (Id)
 * Spigot: The closest thing to an all-rounder (Ego)
 * Rands: Clever and intelligent (Superego)

Nerf Now
While this still is in development,
 * The Artist: A hyperactive tentacle monster person who enjoys puppets. (Id)
 * The Mascot: Calm redhead who manifests as a character in whatever game is played. (Superego)
 * Josue Pereira: A Brazilian with bad luck and too many choices. (Ego)
 * Argumentatively, since these are not active characters in any storyline (save The Mascot), these three characters could also be heteronyms for the real-life Josue, harkening back to Fernando Pessoa, who developed the concept (and is also Portuguese).

Freefall

 * Sam: (Id)
 * Florence: (Superego)
 * Helix: (Ego)
 * In the strictly freudian context, as Helix is effectively a child and both Sam and Florence compete for influence above him, as seen in this strip.

Furthia High

 * Bruce: (Id)
 * Ashley: (Ego)
 * Campy: (Superego)
 * Kale's Multiple Personalities form another one:
 * "Normal" Kale: (Ego)
 * Fox Kale: (Id)
 * Human Kale: (Superego)