The Boss Baby: Back in Business: Magnus always speaks in a loud monotone voice. When asked about it, he claims to have "LOST MY INSIDE VOICE IN AN ACCIDENT."
Histeria! has a character called Loud Kiddington (depicted as page image), whose name should be self-explanatory.
Pepper Mills is also quite prone to yelling a lot, but mostly when she's excited about something (usually meeting a historical figure that she thinks is a pop cultural celebrity).
The character Hollywood's catchphrase was "Isn't that cute?... But it's WROOONNNGGG!!", which was always delivered over the top no matter how minor the matter was. (When he wasn't shouting, his voice wasn't particularly loud, but it still felt loud with a sort of gruff, obnoxious quality.)
And don't forget Little Red Riding Hood, whose voice seemed to randomly fluctuate between what would be expected of a little girl and a yell with an almost foghorn-like quality.
The king of constant yelling, Yosemite Sam, has a voice so loud and boisterous that it eventually took a huge toll on Mel Blanc's voice. (Sam also liked to punctuate his sentences by firing off one or more of the loaded pistols he kept about his person. In case you've only seen guns on television, they are VERY LOUD when they go off in real life.)
Bugs:(impersonating Theodore Roosevelt) I speak softly, but I carry a BIIIG STICK! Sam:OH YEAH? WELL, I SPEAK LOOOUUUDD! AND I CARRY A BIIIIIGGER STICK! AND I USE IT TOO!
Tex Avery's MGM shortRock-a-bye Bear has Spike the Bulldog hired as a winter caretaker for a hibernating bear who keeps demanding quiet in the loudest voice imaginable.
Joe Bear:SHADUP! QUIET! I HATE NOISE! I SAY I CAN'T! STAND! NOOOOISE!
And Scratch takes after him. Kinda justified because he's a robot chicken.
Tommy in The Off-Beats shorts on Nickelodeon had a tendency tosuddenly shout loudlyin a man's voice when exasperated or frustrated, with the words literally flying out of his mouth, startling the others and himself. Occasionally, other characters have been shown to have this ability as well.
Ollie combines this trope with Beige Prose to get the point across...
Tom: And now we go to Ollie Williams with the Blaccuweather Forecast. Ollie? Ollie:IS' GON' RAIN! Tom: Thank you, Ollie.
And of course...
Tom: In local news, we have more on the approach of Hurricane Rupaul as it makes his or her way up the coast. Let's go live to Ollie Williams with the Blaccuweather report. Ollie? Ollie:IS' RAININ' SIDEWAYS! Tom: Sounds rough, Ollie. Do you have an umbrella? Ollie:HAD ONE! Tom: Where is it? Ollie:INSIDE OUT, TWO MILES AWAY! Tom: Is there anything we can do for you? Ollie:BRING ME SOME SOUP! Tom: What kind? Ollie:CHUNKY! Tom: All right, we'll get on that.
From the opening of "Lois Kills Stewie":
Tom Tucker: And now, here's Ollie with a recap of the last episode of Family Guy. Ollie? Ollie:STEWIE KILLED LOIS! Tom: Then what? Ollie:PETER GOT BLAMED! Tom: Then what? Ollie:PETER WENT TO COURT! Tom: Then what? Ollie:LOIS CAME BACK! Tom: How? Ollie:WASN'T REALLY DEAD! Tom: Thanks Ollie, and now part two!
After Tom's son is arrested for possession of drugs:
Tom: The student was sentenced to 200 hours' community service and is a very bad boy. We now go to Ollie Williams for the Punishment Forecast. Ollie? Ollie:HE GON' GET IT!
When marijuana is legalized in Quahog and the entire population is perpetually stoned, he finally speaks in a normal indoor voice.
Tom: How's the weather, Ollie? Ollie: Not too bad.
And then there's Jeff. The closest he ever comes to being Played for Laughs is that he's always screaming even when he has no reason to be angry.
This became a series of segments called "Screaming with Binky", where Binky disturbs someone who is doing an activity that requires concentration, like building a sand castle or making pizza, or animating the show.
Lampshaded in "Fat Man and Little Boy" where Homer is mad about Bart becoming his financial dependent and is yelling. Marge tells him to use his indoor voice, and he replies "I DON'T HAVE AN INSIDE VOICE!"
Lampshaded again in the first part of "Who Shot Mr. Burns?": everyone is complaining increasingly loudly about how Mr. Burns is ruining their lives, to the point where Marge screams, "HE'S CAUSING US ALL TO YELL!" Maggie, being The Voiceless, just sucks her pacifier harder than usual.
Yet another lampshade from "Bart the Mother" brings Milhouse into the act, after Lisa tries to cover for Bart being at Nelson's.
Homer, shouting through the kitchen window:MIL-HOUUUUUSE! Milhouse, from a distance: WHAAAAT?! Homer: TELL BART TO COME HOME! Milhouse: I THINK HE'S AT NELSON'S! Homer: WHO'S NELSON?!
Dora the Explorer is known for talking rather loudly most of the time. Then again, she does spend a lot of time outdoors. It suits the show's attempt to imitate pre-school CD-Rom games.
Lampshaded in "Band Geeks". Squidward mentions that "Being loud makes you sound smart" in response to the mediocre quality of the band he is in (which Plankton backs up by shouting "CORRECT!"). Squidward then goes on to suggest that if the band plays really, really loudly, people will think they're good. Of course, it backfires....
Doctor Byron Orpheus constantly shouts over a blaring, overly dramatic soundtrack.
Orpheus: Do not be too hasty in entering that [bath]room, I had TACO BELL for lunch!
Also, the Grand Galactic Inquisitor shouts everything over its built-in loudspeaker, then shouts, "IGNORE ME!" if someone responds.
The Man Who Yelled, from the Mo Willems short film of the same name.
The Red Guy from Cow and Chicken randomly turns this on and off. The rest of the characters lack inside voices altogether.
Behold!Mighty Thor rejects the notion of an Indoor Voice! Surprising that he doesn't burst Jane's eardrums when they embrace:
Thor:TILL THE UNIVERSE CRUMBLES, MY HEART IS EVER THINE!
The cast of Foster's Home for Imaginary Friends can be easily divided between those who do have an indoor voice (Mac, Herriman, Wilt) and those who don't (Bloo, Cheese, Eduardo, Coco).
One could say Dil, of Stickin' Around has No Indoor Voice, if his voice wasn't ridiculously loud for being Outdoors as well.
From the same series, the Cybernetic Ghost of Christmas Past From the Future. Generally accompanying one of his meandering stories.
In the Daria episode "Fair Enough", Quinn's role in a school play causes her little worry until Sandi comments on the "unusual inflections" in the way Quinn says her lines. This gets under Quinn's skin. A later resultant line is spoken with emphasis on every word: "I will make a dainty garland for my head and sing! Laa, la la LAH!..."
Phil Ken Sebben is a more than a little guilty. "I'M SORRY I CAN'T HEAR YOU, I DON'T KNOW IF YOU NOTICED BUT I'VE GOT JUST THEONE EYE!"
Shado the Brain Thief takes this trope to its logical conclusion. Not only does he have no indoor voice, he has no indoor thoughts. Literally every thought he thinks is broadcast into the minds of everyone nearby at a deafening volume. A custodian takes a broom to a nearby PA speaker in an attempt to silence the noise.
On The Fairly OddParents!, this applies to a lot of characters, including Timmy, Cosmo, Vicky, Crocker, Princess Mandie, and Chloe. Justified by Cosmo in one episode on the basis that "shouting helps you remember things".
Cosmo: BLUE IS A COLOR!
The title character from Invader Zim shouts almost every sentence.
And that's just his regular speaking voice. When the ham turns on, he gets louder.
Apparently, this forced Zim's actor, Richard Horvitz, to work alternative days, as he'd be hoarse at the end of each recording session.
Nathan Explosion speaks with a death metal growl all the time.
And Dr. Rockso the Rock n' Roll clown yells constantly, too. Though there's a reason for that. He likes to remind everyone (and squirrels) that HE DOES COCAINE! A LOT OF COCAINE!
He occasionally says it in creepy whispers. IN BETWEEN LOUD YELLS.
Johnny Test. It seems with every passing season, the characters yell more frequently. Sometimes, the screen even shakes and the ground rumbles when they yell.
Truffles from Chowder. One episode was the primary focus for her voice, when she changes it to a quieter one after her old one scares customers away.
Candace and Dr. Doofenshmirtz (particularly the latter) from Phineas and Ferb.
The Brak Show has Thundercleese, who pretty much shouts all the time, as well as Rhonda of the Seventh Level of Yar:
Mom: Well, Rhonda, I think the table is quite squared away— Rhonda of the Seventh Level of Yar: I AM RHONDA, OF THE SEVENTH LEVEL OF YAR! Mom: Yes, you've mentioned that quite a few times. Is there anything I can do to help in the kitchen? Rhonda of the Seventh Level of Yar: NO! THE FOOD HAS BEEN ARRANGED! Mom: Well then, I suppose we should join the boys in— Rhonda of the Seventh Level of Yar: THE DAY OF JUDGMENT IS AT HAND! Mom: Um, alright, if you say so— Rhonda of the Seventh Level of Yar: YOU WILL BE JUDGED! SO SAYETH THE SCRIBES OF YAR! Mom: You know Rhonda, I'm not even sure if I know where "Yar" is. Rhonda of the Seventh Level of Yar: YOU'LL FIND OUT... WHEN YOUR SOUL IS BELCHED FORTH AND DEVOURED UPON THE SHORE OF THE RIVER OF HEADS! Mom: Oh dear. Rhonda of the Seventh Level of Yar: THE RIVER OF HEADS IS IN YAR! THIS I CAN ASSURE YOU! AH HA HA HA HA HA!
Brak himself has no indoor voice. "HI, MY NAME IS BRAK!!"
Princess Luna, as part of an outdated royal protocol, speaks in a deep booming voice meant to "impress". It doesn't exactly go over well with the citizens of Ponyville. It really doesn't help that it's the same way she spoke when she was Nightmare Moon. Spelling out this Traditional Royal Canterlot Voice in all-caps is referred to as Canterlock.
Luna: But this is the traditional royal Canterlot voice! It is tradition to speak using the Royal "We", and to use THIS MUCH VOLUME WHEN ADDRESSING OUR SUBJECTS.
Bulk Biceps, a comically-muscular pegasus pony from "Hurricane Fluttershy", seems to talk like this. His initial appearances were limited to a trademark "YEAH!!!", while his appearance in Rainbow Falls has other ponies occasionally asking him to tone it down:
Bulk Biceps:"P" IS FOR RAINBOW DASH! Fluttershy:[whispering] Um, "Rainbow Dash" actually starts with an "R". Bulk Biceps:NEVER MIND!
In Adventure Time, Lemongrab seems to have a problem with this. He's almost always shouting or talking extremely loudly. Whether he's aware of this is unclear, as his voice is naturally high-pitched and shrill, and he's almost always angry. "IF ANYONE NEEDS ME I'LL BE TAKING A NAP!!!"
Benson from Regular Show. He actually deafens Mordecai and Rigby one time.
Bill Cipher almost always speaks in a high-pitch, shrieking voice which makes him sound like an evil Disembaudio, a holdover from when he was planned to be voiced by David Lynch.
LEMME TELL YA' SOMETHIN', TV TROPES!! IF YOU DON'T PUT RATH FROM BEN 10 1 MORE TIME, RATH WILL BEAT YOU UP FOR SURE!!
Brattus from Mr. Bogus often speaks like this, due to the fact that he speaks with a gravelly-sounding voice, courtesy of his voice actress, Russi Taylor.
While it may simply be the tone of his voice, rather than volume, Starscream from Transformers (at least his earlier incarnations) fit this pretty well, due to his near-constant screeching tone. Shortpacked!addressed this.
Owan the Oil Rig from Theodore Tugboat is both very loud and easily excited. However, since he is way too big to fit inside inside a building (being that he himself is a building), there's no way he can be indoors, so his loudness is justified.
The Pepper Ann episode "Moose In Love" in which Sean the boy Moose had a crush on always shouted whenever he spoke, it turns out this is because his mother is deaf in one ear and he has to talk loudly for her to hear him.
Daisy from Oswald has a tendency to shout. Oswald has to tell her to lower her voice.
Peppa Pig has Grampy Rabbit, who has a very loud voice courtesy of BRIAN BLESSED. In fact, one can make the assumption that the staff created Grampy Rabbit specifically as an excuse to have Blessed on their show.
Angelica from Rugrats tends to yell more than not, usually to get something she wants. In the first movie, her loud singing is what caused Didi to go into labor a week early.
A few of the characters from Teacher's Pet are voiced by Pamela Segall Adlon (not counting the coolest kids - Tylor, Taylor, Trevor) tend to shout, particularly from Teddy Naven.
Too Loud!: The duo protagonists Jeffrey and Sara have incredibly loud voices. According to Sara, the reason she and Jeffery have such loud voices is that having really big heads made their mouths and throats big as well, causing their voices to be louder than anyone else's.
Loud Howard from Dilbert is an Ascended Extra compared to his role in the comic, probably thanks to a particularly hammy vocal performance by Jim Wise. One episode explains it by showing that his house is near an airport and a railway track.
Ladybird from PAW Patrol, being a Large Ham, is very shouty, especially in the UK dub.
STOP!
Let's Go Luna!: Carmen's pet hamster, Honey, does not speak below a fairly loud shouting voice.