In Deus Ex Equine Revengeance, about half of Facet's dialogue thus far has been devoted to snarking somepony. Rainbow Dash actually stated that he held back in his intro scene because her infant son was present.
Bronzong of the Total Pokémon Island series. Moreso in Total Pokémon World Tour.
Harry becomes exponentially snarky in The Wizard In The Shadows after a start in which he didn't talk much at all, then getting steadily snarkier as time goes on. This is largely a reaction to trauma and his way of dealing with it. The narration is also decidedly lemony.
Narrator: Gimli, having reached the Horn, blew on it, causing one massive, and vaguely flatulent sound to echo over the deep.
Harry: *just after Gandalf frees Théoden from Saruman* Look upon your kingdom once more. I hear it’s very nice this time of year.
Théoden: What does Rohan owe Gondor?
Harry: Would you like me to list that alphabetically, or chronologically?
The Seven Names of Envy Angevin: Envy and Russell are especially prone to this, which is what makes them such good foils to the belligerent Ed and crazily hyper Ling respectively, and makes the banter so entertaining. A sample:
Ling: Besides, you're being childish. I haven't even slept with anybody in...two weeks!
Russell: Oh, how wonderful for you. Here's a memo: giving your pecker a two-week vacation doesn't make you less of a slag.
Scar (at the thought of teaming up with Hago again): Where did that get us last time? Oh, yeah… it got me exiled to this filthy, infested jungle!
Zazu: This is getting tiresome. I'd love to stay and chat, discussing how the names of all my family members are ridiculous and all, but I'm afraid your parents have requested that you are present when they leave.
Simba has a few moments in Dead as a Dodo.
Simba: That would explain why you're no fun.
Zazu: I heard that.
Simba: Yeah, well you were supposed to.
Nala: Now, if we killed somebody - and we have - what would we do?
'''Simba (half-heartedly): Run around screaming and crying?
Apparently, the Royal Guard handbook actually encourages this.
Shining Armor: However, the Royal Guard Regulations state in Rule Four Hundred and Nine, that 'in face of overwhelming stupidity, an officer is permitted to deploy sarcasm'(I appreciate the Princess' understanding of our position).
In Shadow Snark the titular character is, as expected, very snarky.
Shadow Snark: You're sending me to that backwater semi-racist insane asylum to learn about friendship?
Princess Celestia: See this is why you're leaving.
The protagonist of Sophistication And Betrayal has a habit of snarkily lampshading the weirdness found within Equestria. His marefriend Rarity is also quite fond of responding to his antics with snark.
Navarone in Diaries Of A Madman could almost make a career out of doing this. Celestia and Taya show a lighter version of this, usually responding to his antics with the occasional dry and snarky remark.
Several members of the cast of Kitsune no Ken: Fist of the Fox get a shot at this here and there, but one of the main ones is Shikamaru, usually in response to Ino's nutty antics or Choji's appetite. There's also Jugo, regarding anything Suigetsu does, or Kushina, who never fails to take the occasional pot-shot at her own son Naruto.
In "Even The Score", O Cs Ace and Streets are snarkers to the bone. Combined with Jack and Racetrack, all snarky hell breaks loose:
Ace: "Conlon...he called you Cowboy." Jack: "Yeah, so?" Ace: "So does he call ya that 'cause of your taste in hats, or what?"
Streets [referring to a bet]: "Can I get in on that?" Racetrack: "On whose side?" Streets: "Not yours."