Only rule: Keep it appropriate to the Champion. Don't have Swain say goofy things (unless you cite it as a joke quote), and don't have Jinx be serious.
Example
(buying 
) : Give someone a mask, and they'll show their true face.
taunting 
: Boing, boing, boing!
taunting 
: You can't scream? Wow... you're no fun at all...
kills 
: Double-barreled payback. My favorite!
Upon starting a game
Movement
Attacking
Taunt
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Joke
Upon dying
Upon starting a game
Buying a 
Buying a 
Buying a 
Buying a 
(Trololol)
Buying a 4th 
Taunting an enemy 
Taunting an enemy 
Nearby allied killing a Hunted target.
Nearby allied going mega form.
Taunting an enemy
Taunting an enemy
Taunting an enemy 
Taunting an enemy 
Revealing stealthed 
with ultimate.
Revealing stealthed 
with ultimate.
Revealing stealthed 
with ultimate.
Revealing stealthed 
with ultimate.
Revealing stealthed 
with ultimate.
Revealing stealthed 
with ultimate.
Taunting Forecast Janna: "I predict sunshine in YOUR forecast."
Joke: "Squawk!" "Who's there?" "Squaawk!" "Luxanna who?" "Squaaawk!" "You'd better not let HER hear that."
Start of game: "So many victims, so little patience!"; Buying a BF Sword: "Yay! This sword will help me shoot things!"; Buying Hextech Gunblade: "I finally got my new gun! I hope my other guns don't find out."
Buying Guardian Angel: "My kin are watching over me."
PS: In no way do I condone seriously buying Gunblade on Jinx, just as I do not condone Nashor's Tooth on Draven.
Taunts:
to : "He who considers himself the best forfeits the right to be called such."
"Face me! FACE ME, AND EXTINCTION!"
"By the time I'm done, you will beg for mercy. And I will deny you."
Upon selection
Upon starting a game
Movement
Attacking
Taunt
Taunting an enemy 
Taunting an enemy 
Taunting an enemy
Joke Fiddlesticks rips off his head, dangles it, and then puts it back on.
Upon using Terrify
Upon using Drain
Upon using Dark Wind
Upon using Crowstorm
Upon buying
Upon buying
Upon buying 
Upon buying 
Upon placing a 
or 
Upon selling an item
I'm back with more!
Movement
Attacking
Upon casting Bulwark on himself.
Upon casting Bulwark on an ally.
Upon casting Idol of Durand.
Upon buying 
Upon buying 
Upon buying 
Upon buying 
Upon buying
Upon buying 
Upon buying 
Generic taunts.
Generic jokes.
Taunting an enemy (New Sion of course)
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Casting Idol of Durand on any of the above champions.
Upon placing a time bomb on an enemy with less than 10% health
"Face the inevitable."
"Your time has run out."
"Did you see this coming? I did."
Upon death
"I knew that...would...happen"
Upon getting any multikill (double, triple, etc.)
"Now THAT is funny."
Upon killing any Yordle champion except 
or 
Laughs maniacally "You're all so small from up here!"
Upon killing 
, 
or
"My inventions are superior!"
Upon dying while on a killing spree
"At last..."
"My...glorious end"
"Finally"
Upon killing Jinx
"I guess you can make me smile. Do it again!"
Upon killing 
with his ultimate while under the effect of 
's ultimate
"Big fish eats the little fish!"
(playing with her orb) "Bouncy... Bouncy... Bouncy..."
(jiggles her orb) "Mmm, so jiggly"
http://img3.wikia.nocookie.net/__cb20141104215431/leagueoflegends/images/d/db/Dragonzzilla_Nautilus%27_Wrath.jpg Upon selection "Beware the depths."
Upon starting a match "From shadowed depths, I come." "I step ashore." "Roused from the deep." "Time and tide do not wait." "We leave with the tide."
Attacking "All will drown." "Drag them down." "I will have vengeance." "I will not rest." "In over their heads." "They will drown." "They will pay. "Worse to come."
Movement "All things pass." "Beware the undertow." "Do you hear them calling?" "Echoes from the deep." "Fear the ocean's weight." "Find the guilty." "Forward, forward..." "Ghosts of the past linger still." "How long has it been?" "I will follow them into the abyss." "Into waters unknown." "It is a small step for me." "Left to die." "Lost and forgotten." "Peer into the darkness." "Still waters run deep." "The endless march." "The tide ebbs." "They slumber in the deep." "To the farthest shore." "What am I?" "What price have I paid?"
Taunt
"At sea, no one cares for your screams."
"Do not fear. I hear corpses float."
"Cheap caviar."
"Move aside, small fry."
"Sharks know not allegiance. Only blood."
Joke "I won't sing an anchor." "One day there was an anchor..." "Sometimes I think this anchor just weighs me down."
Upon selection
Upon starting a game
Movement
While in combat
Attacking
While in combat
Taunt
Taunting an enemy
Taunting an enemy
Taunting an enemy
Taunting an enemy 
Taunting an enemy 
Joke Tristana puts down her cannon, takes off her sack of cannonballs, and rolls her neck and shoulders.
Joking near an allied
Joking near an allied
Upon reaching level 18
Upon using Rapid Fire
Upon using Rocket Jump
Upon using Explosive Shot
Upon using Buster Shot
Upon using Buster Shot on an enemy 
Upon using Buster Shot on an enemy
Upon selection
Upon beginning a match
Movement
Attacking
Taunt
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Taunting an enemy 
Joke
Upon killing units with Overload
Upon using Rune Prison
Upon using Desperate Power
Upon buying 
Upon buying 
Upon buying
Upon buying
Upon buying
Upon buying 
Upon buying
buying 
: the flames of the sun surround me
Upon starting a game
Movement
Attacking
Taunt
Taunting an enemy 
Taunting an enemy
Taunting an enemy 
Joke Tryndamere plants his sword in the ground and tries to uproot it, eventually falling backwards.
Joking near an allied 
Joking near an allied 
Upon using Mocking Shout
Upon using Undying Rage
Upon placing a or
Upon buying 
Upon buying 
Upon buying 
Upon buying
Upon casting recall
taunting an enemy 
: These shadows are not so easily banished.
taunting an enemy : Your light is nothing to my darkness
taunting an enemy
: I always wanted a pony!
Joke: Skree. Who's there? Skree Shyvana who? Skreeee Valor! I don't want to deal with an angry dragon!
Nunubot taunting an enemy 
Oh great, even stupid bird is here.
This is fun.
Upon starting a match.
Movement
Movement (In combat)
Attacking
Attacking (In combat)
Upon his passive activating.
Casting Grand Skyfall (First quote for jumping, second while falling down).
Upon buying a 
Upon buying 
Upon buying 
Upon buying 
Upon buying 
Upon buying
Upon buying
Generic taunts.
Generic jokes.
Taunting an enemy
Taunting an enemy 
Taunting an enemy
Taunting an enemy or or
Taunting an enemy or 
Buying 
: The only will that matters is mine!
Buying : Your time has just run out.
Buying : I'll show you REAL torment.
Taunting : Stay dead, then I can make use of you.
Taunting : You cannot run from death.
Taunting 
: No, YOUR soul shall come to serve me!
Taunting 
: Even in death your soul will not find her.
Taunting 
: Shall we find out if even a bug has a soul?
Taunting 
: With strange eons even death will die.
Near allied : So...care to trade some souls?
Near allied : Can...Can I ride you?
Game start
Movement
Attacking
Taunt
Joke
Death
Approaching 
Joke near
Approaching 
Taunting
Joke near
Buying 
Buying
Buying 
(After a pentakill): The bird is indeed the word
upon getting a kill- HOW DID I DO THAT?/(happy crying)/ I bet ill never do that again......
upon buying boots, Will these make me look taller?
Trying to think of more....... I tryed very hard to find a quote for my main, Anivia. couldn't think of anything :(.
Final Boss Veigar
After killing a champion with Primordial Burst: "You've met with a terrible fate, haven't you?"
Im really bad at this, but for my two cents I will suggest someone fix 's. Not to say Mrs. Post did a poor job, no no. Her actress is excellent. But her lines dont make sense if shes supposed to like, NOT be killing people anymore. They kinda shot any character development in favor of fan service.
buying a 
or 
"My precious..."
upon /J within 600 units of any female champion - "Rock solid...."
upon buying a 
- "Come here Poro. I have gift for you."
Because is basically a medieval version of the Warhammer 40,000 Space Marine:
On move:
"Demacia's borders are endless."
On attack:
"The soldiers of Demacia know no fear!"
On Q:
"Smite the Heretic!"
On W:
"Demacia protects!"
On E:
"Witness your doom!"
On ult:
"I strike with the wrath of the righteous!"
Upon buying...
"Protection from the storm."
"The winds can tame any shadow."
"A container, forged by the winds."
"What the winds give, the winds can take."
"A witness for the changing winds."
New Selection Quote: "Only you can hear me summoner, Fearless has abandoned me."
Performing an auto-attack with Power Chord active: "Like removing your foot from 'The Pedal'." / "Like playing with a Silencer."
When casting Hymn of Valor: "Pianissimo." / "We are all Second String."
When casting Aria of Perseverance: "Lestara, I will see you again soon." / "The Buvelle estate will soon be empty."
When casting Song of Celerity: "Largo." / "Twenty BPM."
On death: Fearless laughing maniacally
Gentleman
Taunting an enemy :
"Hello, Miss Caitlyn. Care for some tea and cupcakes?"
Getting hit by a Caitlyn Yordle Snap Trap: " This delectable cupcake was well worth the trap, wot wot!"
Taunting an enemy :
"Ah, I've always wanted to engage in a battle of fisticuffs!"
"Miss Vi, I have come to share with a bowl of fruit punch with you!"
Taunting an enemy :
"Your obsession with gems is truly outrageous, Taric!"
"Your armor is well adorned with quality gems. I love it."
Taunting an enemy :
"Sir Vladimir! Does my mere presence cause you to see... red?"
"I do not appreciate the mess you leave behind after a battle, Vladimir."
Taunting an enemy Gragas, Esq.: "Ah, yes! I would love a fine drink from you!"
Taunting an enemy Debonair champion: "I truly think you could use some improvement on your style, wot wot!" "For a Debonair, you are quite uncivilized!"
Buying an :
"Not exactly my cup of tea, but I suppose it shall suffice."
Buying an 
:
"Are we engaging in a duel of fisticuffs?"
Buying a :
"What a fancy hat!"
Buying a :
"I do love masquerade parties!"
Master Yi : Don't fight them while they have baron.
Ok. Ok.
Upon buying certain items
Kk
I'm going to revive this thread. It was so much fun, before. And, I'll bring new quotes!
Champion Selections:
Upon starting a match:
Upon starting a match of Dominion or Ascension:
Movement:
Attacking
Upon capturing a Crystal Spire
Upon slaying an enemy near a captured Crystal Spire:
Upon casting Impale
Upon pulling an enemy with Impale next to an allied Crystal Spire:
Taunting
Taunting an enemy 
:
Taunting an enemy 
:
Taunting an allied 
:
Taunting an enemy :
Taunting an enemy :
Upon purchasing 
:
Upon purchasing 
:
Upon purchasing :
Upon purchasing 
:
Upon purchasing 
variation or :
Upon purchasing :
Upon death:
Ruthless needs some variation of...
"Hi, my name is Pantheon, warrior of Mt. Targon and defender of Castle Moonskull... and this is my faithful companion, Crengar (Cringer/Rengar) Fabulous secrets were revealed to me the day I held aloft my magic spear and said 'Kill da Wabbit!.' "
: What I have done CAN be undone
(Upon using undo in the shop)
(taunt) "Blood is thicker than water? Crystal is harder than flesh! My people will walk once more ... upon your corpse."
When taunting a nearby enemy :
-Normally before destroying you I'd analyze your knowledge... but it seems like you like the brain to contain such knowledge.
Upon buying
-Such torment must hold great wonders.
