CANON
Discord: http://discorderlyconduct.tumblr.com/
Queen Chrysalis: http://cupidite.tumblr.com/
Pinkie Pie and Fluttershy: http://askfluttershyandpinkiepie.tumblr.com/
CMC: http://ask-thecrusaders.tumblr.com/
Twilight Sparkle: http://ask-twilightsparkle.tumblr.com/
Applejack: I'm really, really sorry... but I forgot. I tried looking around and asking my artist friends, but I can't figure it out. Please let me know if you do know who it is!
Lightning Dust and Gilda: http://tworuffledfeathers.tumblr.com/
Applebloom: Tumblrpon's first drawblog, long-since dead. Can't remember the original URL.
Princess Cadance: http://ask-cadance.tumblr.com/
Spike: http://spike-replies.tumblr.com/

FANON
Silverspeed: http://ask-silverspeed.tumblr.com/
Twist: http://ask-twist.tumblr.com/
Carrot Top: http://questionthecarrot.tumblr.com/
King Sombra: http://ask-king-sombra.tumblr.com/ (He's there, you just gotta look! Hint: Berry Punch)
Berry Punch at top-right: http://ask-berry-punch.tumblr.com/
Octavia: http://askoctavia.tumblr.com/
Fiddlesticks: http://fiddlesticks-answers.tumblr.com/
Ace: http://ask-the-ace.tumblr.com/
Featherweight: http://featherweightresponds.tumblr.com/
Derpy Hooves: Same as the Applejack above, unfortunately. Let me know if you know who it is!
Berry Punch at bottom: http://letsaskberrypunch.tumblr.com/
Ruby Pinch with wat expression: http://askpinchy.tumblr.com/
Ruby Pinch with happy expression: http://askrubypinch.tumblr.com/
Lyra and Bonbon: http://ask-lyraandbonbon.tumblr.com/
Raindrops: http://raindropsanswers.tumblr.com/
Pinkamena: http://questionpinkamena.tumblr.com/
Lunar Guards: http://askthenightguards.tumblr.com/

CHARACTER + QUIRK I
Trixie as a filly: http://askfillytrixie.tumblr.com/
Sweetie Belle at top: http://ask-bloody-sweetie-belle.tumblr.com/
Octavia with gun: http://ask-mafia-octavia.tumblr.com/
Twilight Sparkle as a fish: Same as Applejack and Derpy above. I guess that's what I get for not writing these down...
Applebloom with a bandana: http://askbadbloom.tumblr.com/
Princess Luna at top-right: http://captainluna.tumblr.com/
Princess Luna at left: http://luna-afterdark.tumblr.com/
Twilight Sparkle that is half-transparent: http://friendlytwilight.tumblr.com/
Surprise: http://asksurprise.tumblr.com/
Twilight Sparkle as a blob: http://askmlcblobs.tumblr.com/
Sweetie Belle at right: http://askmeaniebelle.tumblr.com/
Scootaloo as a robot: http://askscootabot.tumblr.com/
Pinkie Pie with firey eyes: http://askhotbloodedpinkie.tumblr.com/
Scootaloo with hat: http://scootalootheadventurer.tumblr.com/
Princess Celestia being drunk: http://ask-drunkcelestia.tumblr.com/
Octavia with glasses: http://swagtavia.tumblr.com/
Twilight Sparkle with no mane: http://askcancerpatienttwilight.tumblr.com/
Rainbow Dash with eyepatch: http://askpiratedash.tumblr.com/
Rainbow Dash snuggling up with bandaged pony: http://bandydash.tumblr.com/
Sweetie Belle at bottom-left: http://post-crusade.tumblr.com/
Pinkie Pie with derp face: http://bubbleberry-answers.tumblr.com/
Spitfire: http://ask-cyberpunkspitfire.tumblr.com/
Pinkie Pie with glasses: http://askpinkiepiesolutions.tumblr.com/
Scootaloo with muscles and batwings: ax-brutaloo.tumblr.com/‎
Vinyl Scratch: http://ask-filly-vinyl.tumblr.com/
Princess Luna at right as a human: askhumanluna.tumblr.com/‎
Doctor Whooves with steampunk goggles: askclockwisewhooves.tumblr.com/‎
Big Macintosh on fire: ask-grimdark-bigmac.tumblr.com/‎

CHARACTER + QUIRK II
Rarity with blue-striped mane: ask-acetic-rarity.tumblr.com/
Rarity as a spider: http://spiderponyrarity.tumblr.com/
Fluttershy with goggles: http://ask-dr-adorable.tumblr.com/
Twilight Sparkle with sword: askninjatwilight.tumblr.com/‎
Snails with makeup: ask-glittershell.tumblr.com/‎
Twilight Sparkle with cardboard wings: ask-fillytwilight.tumblr.com/‎
Lightning Dust: askincompetentlightningdust.tumblr.com/‎
Discord as a kid: ask-kid-discord.tumblr.com/‎
Applejack with background: asklyingapplejack.tumblr.com/‎
Applejack with horn: http://ask-alicornapplejack.tumblr.com/
Octavia with arm-magic: askscribbleoctavia.tumblr.com/‎
Sweetie Belle with jets: http://sweetiebotreplies.tumblr.com/
Scootaloo with child: http://motherlyscootaloo.tumblr.com/

CROSSOVER
Ikea pony in top-left: http://askikeapony.tumblr.com/
Master from doctor who: askthetimemaster.tumblr.com/‎
Karkat: http://ask-karkat-pony.tumblr.com/
Firefox: ask-firefox.tumblr.com/‎
Slenderpony: ask-pinkieandslendy.tumblr.com/‎
Doctor Whooves in top-right: askthedoctorallons-y.tumblr.com/
King Candy and Vanelliope: http://ask-king-candicorn.tumblr.com/
Kirby: http://ask-pony-kirby.tumblr.com/
Ridgedog: http://asktheyogponies.tumblr.com/
Applejack in black and white: http://fullmetalapplejack.tumblr.com/
Pinkie Pie as a troll: http://ask-mlpstuck.tumblr.com/
Twilight Sparkle as a sailor: http://asksailorponies.tumblr.com/
Videogame ponies at bottom-right: http://asktheconsoleponies.tumblr.com/

OC (Referring to http://i.imgur.com/Xznl4OL.png)
1: askflufflepuff.tumblr.com/‎
2: askloveletters.tumblr.com/
3: askspirit.tumblr.com/‎
4: askaregularpony.tumblr.com/‎
5: ask-firenze.tumblr.com/‎
6: ask-frigiddrift.tumblr.com/‎
7: http://chocolatepony.tumblr.com/
8: ask-wiggles.tumblr.com/‎
9: asklaurastuff.tumblr.com/‎
10: http://sketchy-replies.tumblr.com/
11: askshinytheslime.tumblr.com/
12: asksweetstar.tumblr.com/‎
13: http://askearthairandmagic.tumblr.com/
14: askpalette-swap.tumblr.com/‎
15: hothlonianponies.tumblr.com/‎
16: queenfrau.tumblr.com/‎
17: thetalesofwildcard.tumblr.com/‎
18: http://askyourgunrunner.tumblr.com/
19: http://ask-crackpot.tumblr.com/
20: askcutiepie.tumblr.com/
21: askvaudeville.tumblr.com/
22: http://askivory.tumblr.com/
23: http://soggiestfries.tumblr.com/
24: asklittlericepaddy.tumblr.com/
25: askturnorder.tumblr.com/‎
26: askrockin-roolo.tumblr.com/
27: http://inkblot-answers.tumblr.com/