From the darkling woods they come, On cloven hoof and twisted claw The Beastmen they are called, these ones; Less than human, yet also something more. — From the Strange Tale of Doctor Malfeasant, Warhammer
Kiba of the Inuzuka Clan from Naruto is sort of like this, and he uses it to full advantage in his fighting style.
Hoshigake Kisame, an antagonist from the same series, is a more literal Beast Man, with distinct sharklike features and an attitude to match.
The antagonists in the first half of Tengen Toppa Gurren Lagann - They're even called Beastmen. They were uplifted from regular beasts to provide Lordgenome with an army that couldn't harness Spiral Energy due to not undergoing evolution.
In Mahou Sensei Negima!, these, together with Petting Zoo People, Demons, and other non-human humanoids, make up most of the Southern Empire in the Magic World. Specific examples include the chief waitress Apron Matron bear woman named Mama and the tiger man in Negi's first match as a prized fighter. Kotaro can turn into a Wolf Man in his demon form.
Tony Tony Chopper's Third and Monster form from One Piece. Most Zoan's halfways forms count too.
As the series carries on in Fullmetal Alchemist the Chimaera stop being Mix-and-Match Critters and end up becoming more like these, by the end of the series we have a gorilla, a hog/porcupine mix, a frog or toad...thing, and a lion.
Franken Fran's Gavrill is a "transformer", a person with a sectioned body and complete control over its shape, is capable of turning into giant wolf-like beast with two rows of teeth. She also possesses Super Senses and acts the part, being the vicious leader of a gang of murderous outlaws.
Beast originally was a more or less normal appearing *
(insofar as it's possible to tell given the artist — Kirby may have been a genius, but his faces tended to fall firmly in Uncanny Valley territory)
muscular stocky guy with enormous hands and feet. He still got much the same reaction though, because people didn't expect a guy with gorilla hands to be sensitive and well-educated.
Wolverine and more so, his old enemy Sabertooth. Interestingly Wolverine didn't start out this way, but fell into it as writers delved into his character. Then Sabertooth was introduced, and he was deliberately turned into this (from a non-powered Serial Killer with fake claws in Power Man and Iron Fist) to act as a Not So DifferentEvil Counterpart to Wolverine.
Marvel's New Men are animals evolved by the High Evolutionary into intelligent humanoids. The Ani-Men are humans mutated into humanoid animals.
Beast Boy, who can turn into any animal he thinks into. He's more animalistic in the cartoon than in the comics, though.
Every few years Spider-Man winds up more spider than man. He always gets better. His enemies The Lizard (usually animalistic) and The Jackal (usually a Mad Scientist) definitely qualify.
Batman's recurring foe Killer Croc falls into this quite often, but can get quite silly considering his official origin is a "skin condition", which doesn't really explain why some versions of him have a tail. Hand Waved by having Hush infect him with a virus that speeds up his 'devolution', causing him to develop more bestial traits.
Barf, the Mog (half man, half dog) from Spaceballs.
The Big Bad of The Wheel of Time has the Trollocs, a breed of humans bred to be closer to animals, with hawk's heads, goat's heads and whatever you can think of.
Perrin is a rather good example as well, as his status as a Wolfbrother means he constantly struggles to stop his wolf side overwhelming his human side.
The Cthons from Michael Reaves' The Shattered World and The Burning Realm sure looked like Beast Folk, and had the usual abilities associated with this trope, Healing Factor and communication with animals in particular. Subverted in that they were demonic creatures rather than bestial humans.
In the Kate Daniels universe, the more powerful shapeshifters can develop a form halfway between human and beast, known as the warrior form. This form is more dangerous than either of the others, and being in this form is legally equivalent to being armed with a lethal weapon.
“Conan”, he whispered, “it was no man that stood before me! In body and posture it was not unlike a man, but from the scarlet hood of the priest grinned a face of madness and nightmare! It was covered with black hair, from which small pig-like eyes glared redly; its nose was flat, with great flaring nostrils; its loose lips writhed back, disclosing huge yellow fangs, like the teeth of a dog. The hands that hung from the scarlet sleeves were misshapen and likewise covered with black hair. All this I saw in one glance, and then I was overcome with horror; my senses left me and I swooned.” “What then?” muttered the Cimmerian uneasily. “I recovered consciousness only a short time ago; the monster must have thrown me into these pits. Conan, I have suspected that Nabonidus was not wholly human! He is a demon — a were-thing! By day he moves among humanity in the guise of men, and by night he takes on his true aspect.”
For reference, they have the power to mate with anyanimal
in the world, and once they do, the baby eats its way out of the pregnant animal with the attributes of its parent. You may barf now.]]
Nearly all of the less civilized races of Talislanta fit this trope, to a greater or lesser degree. Even Archeans, the setting's human-analogs, are descended from Beast Folk who used magic to eliminate their more animalistic traits.
The Gangrel from Vampire The Masquerade and Vampire The Requiem. They have a clan-specific Discipline that allows them to grow claws and turn into beasts. they're short-tempered and feral, and in Masquerade, they start taking on animalistic features whenever they go into Frenzy. Members of the Nosferatu clan from Vampire The Masquerade often embody this trope as well. They are the vampires who become monstrously deformed during their transformation. While the deformity can be of any sort (anything from a merely off-putting aura to a virtual Quasimodo appearance to a traditional Count Orlok look), Nosferatu often suffer from fur, claws, bestial teeth, scaly skin, pointed ears, maned hair, an animal stench, reptilian eyes, or some other outwardly animal trait.
And in one of Requiem's Sourcebooks, Shadows of Mexico, there's a Gangrel Bloodline called Dead Wolves, who have some werewolf-related powers, can transform into a hairy, ferocious and literal Wolf Man. Considering that they can only use this power when they are "riding the wave" the savage part is quite intense.
Werewolves in both Apocalypse and Forsaken, but that kind of comes with the territory. Notable that in both lines, werewolves who grow more powerful grow more bestial and fierce, to the point that it freaks normal humans right the fuck out.
The Beast Seeming from Changeling The Lost, who were taken by the Gentry and made into pets and prey. They're much more human when they escape from Arcadia, but they still have trouble thinking logically and have an easy time understanding animals.
Devourers from Demon: The Fallen, who were originally in charge of the sixth day of Creation (when all the animals came into being). They have control over beasts, flesh, and plant life, and they're quite angry about the current state of the world.
In Video Game/Mabinogi, the elves and giants can attain a Beast Mode transformation after a small number of quests. (Humans have transformations, but it doesn't really count for this trope.) To be honest, the giant's transformation fits this trope better than the elven one, though.
Beastmen were a unit/general type in Dragon Force, with the country of Bozack being primarily made of them.
Xenogears contains a race of beast men, including cowardly merchant ratman Hammer and BlankaExpy Rico. Unfortunately, die to the infamous time and money constraints, their story arc is never completed.
The main force of the Beast armies in Armies Of Exigo (often referred to as Kobolds) are this to a T. They're humanoid with vaguely animalistic features, a tribal culture, and savagery that seems ingrained into them. Their troop-types include Witches, Minions, Warriors, and Berserkers. They favour axes as weapons, have longstanding alliances with Ogres, Trolls, and Lizard Folk, and utterly despise humans.
Moogles, appearing first in Final Fantasy III and then every game from V onwards, are generally a gentle, small, and comical race as befitting their mole / bat inspiration as opposed to most examples of this trope.
Final Fantasy V has the werewolves of Quelb, who aren't very bestial besides appearance.
Final Fantasy XI has the Galka and Mithra PC races which fall under Petting Zoo People, but also sports a large number of evil enemy beastmen races including fairly beastial Orcs, Bugbears, and Trolls.
Final Fantasy XII and other Ivalice games have a number of beast men races including the ill-tempered Lizard Folk Bangaa, the Type I Orc-like Seeq, and the insectoid territorial Urutan-Yensa. Subversions include the wise and sagacious Nu Mou and the peaceful, plains-dwelling Garif.
Final Fantasy XIV as an online game like FFXI, has a few beastmen enemy races like the Kobolds and the Ixal.
The Castlevania series, despite werewolves being a common enemy, have tribes of multi-animal shifters called beast men, Cornell from Castlevania: Legacy of Darkness and his rival are a werewolf and a werecat, respectively. They don't serve Dracula, being nomadic from what little backstory the tribe itself gets.
Golden Sun: Dark Dawn introduces a race of Beastmen who were transformed in the wake of the titular event at he end of the second game. The somewhat odd difference is that some Beastmen were transformed from Humans, while others were once animals.
In The Gamers Alliance, the Beastmaster (aka Maiyr Korath) looks beastly due to a magical transformation which turned him from elf into a beast, and he has the ability to mutate and command various beasts of the forest with his chaotic magic. He puts his skill to good use when he sends his beastly minions to openly attack the elven capital Sanae during the Great War.
The creepypasta creation known as "The Rake". A furless dog-man...creature...designed to land smack in the middle of the Uncanny Valley. Oh, and he's started showing up in Everyman HYBRID. As if The Slender Man wasn't enough for those guys to worry about!
The shaggy, cave-dwelling Beast Men in Filmation's Flash Gordon. Dr. Zarkov theorized that Ming was deliberately keeping their civilization from advancing just because he enjoyed having a tribe of savages who would worship him.