Users are able to demonstrate brutal aptitude and great proficiency in using hammers to inflict heavy blunt force damage and/or trauma, making the user very dangerous in close quarters combat. The user can also break down structures and take out heavily armored enemies.
Grunbeld, the Great Flame Dragon (Berserk)
Beluga J. Heard (Black Cat) turning his Verethragna bazooka into a hammer with destructive striking force.
Havel the Rock (Dark Souls) wields Dragon Tooth, a legendary great hammer made from the tooth of an everlasting dragon.
John Henry Irons/Steel (DC Comics)
Suzuno Kamazuki (The Devil is a Part-Timer!), wields a massive hammer with ease despite her petite size.
Puppetmon (Digimon), wielding its revolver-styled Bullet Hammer, which will vanquish the targets via hammer impact and gunpowder blast.
Elma (Hybrid × Heart Magias Academy Ataraxia)
Hammer Kirby (Kirby), wielding a hammer after absorbing an enemy with the hammer weapon.
King Dedede (Kirby), wielding his signature hammer.
Thundering Rhino (Kung Fu Panda), wielding his Cloud Hammer with great skills and strength, famous far and wide.
The Sacred War Hammer of Lei Lang (Kung Fu Panda: Legends of Awesomeness) is a weapon of mass destruction that causes anything it strikes to explode.
Link (The Legend of Zelda), wields many hammers for battle and other purposes, the Skull Hammer being the biggest.
Thor Odinson (Marvel Comics)
Beta Ray Bill (Marvel Comics)
Eric Masterson/Thunderstrike (Marvel Comics) wielding the enchanted mace known as Thunderstrike. The mace granted him a number of superhuman attributes, many of which are conventional among the Asgardians.
Jinin Akebino (Naruto) using the hammer of the Bluntsword/Blunt Blade the Helmet Splitter: Kabutowari to increase the axe's strength, or by itself to create shock waves
Rachel (Ninja Gaiden) is a powerful Fiend Hunter, with her favorite weapon being her signature Inferno Hammer.
Usopp (One Piece) can use his work hammer as an improvised weapon, able to send a Fishman flying.
Buttercup, (Powerpuff Girls Z) can wield her hammer with great strength.
Like her brother, Doronea (Shinju Nectar) is a highly skilled dwarven warrior with her war hammer...
...easily overpowering a battalion of soldiers with great ease.
Amy Rose, (Sonic the Hedgehog) wielding her signature Piko Piko Hammer with great force, despite her delicate-looking build.
In Sonic Adventure, Amy Rose (Sonic the Hedgehog) gained the Long Hammer to increase her striking strength and range.
Rosy the Rascal (Archie's Sonic the Hedgehog), is Amy Rose's evil counterpart, and wields the more deadly Anti Piko Piko Hammer.
Sardonyx, (Steven Universe) uses a war hammer made from Garnet's gauntlets and Pearl's spear.
Mario and Luigi (Super Mario series) both wield hammers with great skill. For example,...
...Mario using the Luiginary Hammer for great destructive force.
Leatherface (Texas Chainsaw Massacre series)
Toby Domzalski (Trollhunters: Tales of Arcadia)
Ultra Magnus, (Transformers: Prime) using the massive hammer, Forge of Solus Prime, with great skill and power, even if it was only for a short time.
The Time Magic Hammer (Yu-Gi-Oh!), can open a time hole that absorbs the opponents.