Judgement of Shamash (Honkai Impact 3rd); Greatsword Form
The Colossus Titan (Attack on Titan) can generate an enormous explosion, large enough to level Shiganshina, by transforming from its human form to its Titan form.
Genryūsai Shigekuni Yamamoto's (Bleach) Ennetsu Jigoku would have destroyed the entirety of Karakura Town.
Ulquiorra Cifer's (Bleach) Lanza del Relámpago produces an explosion that dwarfed even the city-sized fortress of Las Noches.
Gin Ichimaru's (Bleach) Kamishini no Yari extends his blade to such lengths, he can cut an entire city in half.
Tier Harribel (Bleach) using Cascada, which generates a tsunami-sized torrent of water that leveled several city blocks.
Gremmy Thoumeaux (Bleach) and his copy materialize a meteor the size of the Seireitei, which would have destroyed the entire city and its surroundings.
...only for Kenpachi Zaraki (Bleach) to destroy the city-sized meteor with one slice of his Nozarashi.
Lille Barro (Bleach) using Trompete, a massive spatial blast that vaporized a large part of the Wahrwelt city.
Ethereal (Disney's Aladdin) was a near-omnipotent entity that existed to judge civilizations, any that failed her judgment would be destroyed in entirety - she threatened to do so to the city of Agrabah but ultimately spared it due to Jasmine's love for her people.
Cell (Dragon Ball Z) using Super Big Bang Crash to destroy several island cities.
Majin Buu (Dragon Ball Z) using his Flame Shower Breath to destroy a city.
Super Buu (Dragon Ball Z) using Ill Flash to blow an entire city away.
Bruce Banner/Hulk (Marvel comics) is infamous for the massive destruction that follows his rampages.
Nitro (Marvel comics), after supercharging himself, once leveled several city blocks and killed hundreds of people with a single explosion.
King Ghidorah (MonsterVerse)
Kurama, the Nine-Tailed Fox (Naruto)
Nagato/Pain (Naruto) using Shinra Tensei/Almighty Push to destroy the Leaf Village.
The Ten-Tailed Beast (Naruto) generating a massive Tailed Beast Ball with enough power to destroy a distant city.
Charlotte "Big Mom" Linlin (One Piece) leveling Sweet City during one of her rampages.
Edward "Whitebeard" Newgate (One Piece) using the powers of the Gura Gura no Mi to create "quakes"...
...capable of devastating the entire Marine HQ.
Monkey D. Luffy (One Piece) using King Kong Gun to devastate Dresrossa's capital city.
In his Dragon form, Kaido (One Piece) is so large and possesses so much raw power he can destroy an entire city by accident.