"I've never actually hit anyone with it at level ten, but I tried it on a steak once. Vibrated the thing so hard the meat not only cooked to medium rare, but I ended up with quite possibly the most tender cut of beef you could imagine as the connective tissues and bones were practically liquefied." A gruesomely amused grin crossed the man's face. "I could cut it with a plastic fork. Can you imagine what it would do to a human body?"
He also has an energy-efficient teleportation device that can also be used as a microscope, telescope, MRI, scrying device, and video phone.
In Dragon Age: The Crown of Thorns, resident Badass Longcoat elven blood mage Alim Surana came up with magical runes and glyphs capable of keeping the party camp warm during winter. He also uses his frost magic on a pair of chests where they store meat, making them something like portable freezers.
Then, there's the enchantment used by the dwarves, which includes self-filling basins of self-purifying water (these things actually show up in the official book 'Dragon Age: The Calling' too) and metal, runed disks that act as portable campfires/grills -they are made of several, rotating, concentric disks that can be moved to make several rune patterns, enabling red hot iron and several intensities of actual flames.
In Team 8, Naruto's Shadow Clones are useful for getting the D-ranked missions done more quickly. He uses them to cheat on his Chunin Exam test, but not realizing that he receives information from clones that are dispelled, he uses them to see the answers and send him signals.
Naruto also sends his shadow clones shopping on several occasions.
A Drop of Poison is a For Want of a Nail fic where Iruka is poisoned during his fight with Mizuki and can't promote Naruto to Genin; with a lot of free time on his hands until Iruka recovers, Naruto learns to exploit his Shadow Clones to write down all the techniques in the Forbidden Scroll he stole (by using clone version of the scroll, at that) and test them out. Later in the story he creates two new personas to go to school with him for his next year in order to get an unbiased education and manages his own spy network throughout the Elemental Nations. He also uses the clones with various Henges to get better prices while shopping, a instance much more in common with the trope.
In The Return one of the awesome powers of the Succubae is the ability to magic up your own clothing. So if the protagonists see a dress they like in a shop they just need to try it on in the changing room to see how it looks, then once they are out of the shop they magically summon an exact copy out of thin air. Summoned clothes will also dissolve once they are taken off, so it must save a small fortune on dry cleaning too.
In With Strings Attached, the four are Actual Pacifists who get infused with a huge amount of magic, so of course they dick around with it a lot. Two examples are John, who, when bored, starts making the people around him thirsty or sweaty or “desirous of urinating”; and George, who shaves by turning into himself clean-shaven.
Touhou fans love to depict various powers used for mundane or silly reasons. Even beyond all those mentioned below, Suika using her manipulation of density to collect small things - and growing to giant size to easily collect lumber by plucking whole trees as though they were carrots - Aya using her Super Speed to aid in her role as the local Intrepid Reporter, Cirno being used as air conditioning, Yukari using her gaps for pranks, and many, many other variations exist.
Racer And The Geek describes assault rifle bayonets and magazines being used for mundane tasks like food preparation, bottle opening, paper weights, cutting bandages, and pulling nails.
The mundane utility of most things from Lyrical Nanoha is explored in In The Service, from using flight magic letting someone avoid pressure-based traps to telepathy being used for privacy or in loud environments. Some of the more worrisome aspects are also examined, like being able to cauterize the wounds your Flaming Sword causes while it is causing them being handy for cutting off people's bits as a torture technique.
Game Theory also examines possible uses of magic from Magical Girl Lyrical Nanoha in day to day life, such as using magical constructs as Impossibly Cool Clothes. There's also a magic system designed primarily around constructing buildings and other forms of infrastructure that gets mentioned in the world building.
Queen of All Oni: When Ratso gets the Razor Khan mask, Jackie worries over what Jade will do with two armies of Shadowkhan at her disposal. We then cut to her pitting her ninja against Ratso's... in a baseball game.
The first thing Jade is seen doing once she learns about her contortionist abilities is using them to win a bet against the Enforcers (unhooking her jaw in a snake-like matter in order to swallow a massive sandwich whole).
Jade gets this a lot — her magic fans were created to serve as Magic Wands, which they do. But at one point she uses one to, well, fan herself with.
In the chapter that we really see the new haunted mansion headquarters for the Shadow Hand, we see a Shadowkhan vacuuming, showing that Jade uses her Mooks for chores.
In the Ponies Of Olympus series, Rarity is probably Lao Wu's greatest student ever. She uses the fighting skills he gave her to help in her dressmaking (and occasionally, acupuncture).
"Merlin's cooking a three hour meal in half an hour. He’s using a time spell, taking the inside of his cooking pot through time faster than the rest of us. Cully, listen to me – he’s using the level of magic that it would take me a lifetime to learn, and he’s using it to make stew."
"That man has serious power! And he’s using it to make stew! I ask you, what the hell is that about? Stew, for pity’s sake! Who uses power like that for something so stupid? It’s the power of the universe, not a … a… God, why stew, Cully?
KPNY Radio has the characters create a device called the Quantum Entanglement Dish (QED), through which they make First Contact with Earth. They decide to use this miraculous discovery...to start a radio show reviewing works by the bronies.
In Fearful Symmetry when stranded and starving in the wilderness Light uses Death Note pages for kindling and in a moment of insanity eats a page.
The Reading Rainbowverse version of Octavia developed a split personality in order to deal with the trauma of seeing her father almost cut open. She was unaware of this for most of her life, referring to Philharmonica as her "sister", but once she did realize what was happening... she promptly figured out how to switch to avoid hangover pains.
Beneda can form Shiruken on her arms. They're great for helping Kasumi chop vegetables.
The "magic artifact" that Ranma and Ryoga use for their ceremony is used to boil water.
In Arads Stardust, this describes Twilight Sparkle's use of her powers, to the bemusement of XCOM. Telekinesis that can crush a Chryssalid to a smear in one pulse or drive solid steel two inches into concrete? She uses it for tidying up after herself. A spell that renders the target completely silent, so even their actions make no noise? Perfect for silencing an annoying woman teasing you. Inverted in that X-Com is at least considering trying to weaponize any spell that seems it might be useful, such as using the "wallflower" spell so the media doesn't notice them on missions.
Pokemon The Great Adventure gives us Silver, a silver-haired man wearing a full-black outfit and a pretty nice cape. Said cape is often used as a pillow, blanket, a bag ... Ash even notes how warm it is.
In Black Flames Dance in the Wind, Naruto uses his near mastery of fire to clean himself by incinerating everything off his body. He does note that he has to "air himself out" afterwards as it leaves him smelling strongly of barbeque and tends to attract animals.
In Thanks Kyubey, Homura uses her time-stopping powers to cheat in an eating contest against Kyouko.