In Kyon: Big Damn Hero, Yuki used her data manipulation powers to slow the relative time around a tea kettle preventing its tea from cooling down.
Not In Kansas: Kara uses her super speed to play ping pong against herself in two different versions of her Supergirl outfit.
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 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.
In Tangled Adventures In Arendelle, once she got control of her powers, Elsa's now able to use them for things you might not think about. Not only can she give herself a quick change when necessary, but it also works well for giving herself a royal seal or turning out the lights when she's in bed. (they use oil lamps around the castle.)
Ice in Timex... keeps on ticking uses her powers to create ice at ice plants to make money. They save power, and she gets half the money they saved in power bills. According to Fire, she makes enough money to pay for the rent of a penthouse in Metropolis. Killer Frost remarks that she should try going legit.
The Difference One Man Can Make: Harry's magic, which makes him one of the most powerful people in Westeros, is used to make crops grow faster, create buildings within days, construct ships that are Bigger on the Inside and can run faster than the norm...
At one point in The Gift, Rei and her sisters use the fact they now have over two dozen bodies to play a game of baseball.
When Harry gives his new lightsaber to Dobby (at least partially because it's pink) in I Still Haven't Found What I'm Looking For, Dobby figures it'll only be useful for slicing bread and making toast at the same time.
"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 Fearful Symmetry when stranded and starving in the wilderness Light uses Death Note pages for kindling (the Death Note never runs out of pages so he'll never run out of fuel) and in a moment of insanity eats a page.
In Sex Note, when Light figures out the notebook works (despite the name, with it the user can alter people however they want, not necessarily for sex-related reasons), he immediately changes things about himself such as increasing his strength, speed, and giving himself complete immunity to all diseases. Also, he never needs to shave again, his tan is even, and his hair is always perfect.
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 the Transcendence AU, Dipper becomes an immensely powerful dream demon, who could probably bring about The End of the World as We Know It within a few years of gaining his powers if he felt like it. Instead, he spends most of his time hanging around his sister and her husband at the Shack, where they summon him with great frequency (to the point where he gives out a separate circle to friends and family) and make deals for things like candy in exchange for doing the dishes or transportation, or a few raw steaks in exchange for babysitting the kids. This trait isn't limited to people who know of his human side, either; there has been at least one incident of someone summoning him for help with math homework.
In another story (I don't remember which), Harry was sent to Azkaban before his innocence was finally proven, and he swore never to return to Britain until all the people that voted for his imprisonement were dead, too. When that happens, he sets out to kill Voldemort and the Death Eaters... and uses his magic as "special effects" to make a film, using Voldemort as the bad guy. It becomes a relatively low-budget film with special effects that ILM would kill to have, and he and Remus make money hand over fist with that film and the next three. It also credits "Tom Riddle" as a stuntsman in all four films, and he decides not to return after the fourth.
In Chapter 152 of Odd Ideas, Remus manages to find a way to destroy Dementors: put them in a blast furnace where steel is made. As a side effect, the metal stays at low temperatures, and someone theorizes that it could be used to make a soul-eating sword. Remus and Sirius, however, have a much better use for it: keep their beers cold without using cooling charms.
Discussed in Breath of the Inferno where part of why Harry finds Quidditch boring, besides preferring to fly on his own, is that as a dragon animagus (specifically a dragon based on Smaug) he can sense gold and thus always knows exactly where the snitch is.
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 manner 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. This is referenced again several chapters later, when another Shadowkhan is seen dusting a chandelier.
In Queen Of Shadows, Jade at one point wonders if the Shadowkhan use their bladed weapons to help tend to the Fortress' gardens.
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.
"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?
In possibly one of the biggest examples of misuse of Divine Power, Excolotis from I Am War uses his innate abilities as the War God to beat Twilight at a game of darts.
KPNYRadio 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 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).
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 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.
Fallout: Equestria - Empty Quiver features the Princess-class Heavy Cruiser HMS Cadence, a pre-war warship mounting eight 203mm long range guns in four turrets and several still fully functional anti-aircraft cannons and ammunition aboard. Nowadays it's a radio station.
In The Third Generation, the G3 ponies are amazed to see Twilight Sparkle use her gift of magic (something very rare and spectacular to them) for something so mundane as to pick books off high shelves. (Of course, for the G4 ponies, magic is commonplace and ordinary, especially telekinesis.)
Pony POV Series: Prince Blueblood has X-Ray Vision. It helps him find his way around unfamiliar places and lets him check on who is knocking on his door so he can ignore those he doesn't want to talk to.
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.
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 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.
In Advice And Trust, Ritsuko and Maya use their sysop access to the most advanced computer in the world to flirt by leaving messages in the change log (they also use it to plot how to take down Gendo's scenario, but mostly to flirt).
In a general sense, there exists large amounts of fanarts where trainers and pokemon alike use and misuse their powers in a variety of ways. For example, artist Sougetsu's comics starring Gardevoir and a "Princess" Lilligant have the characters using their powers in all sorts of ways, like Gallade misusing Trick to swap a bag of rubbish onto some random person.
Pokémon: 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.
The PokeumansFan Verse has produced several ways in which being a Pokemon gives you various abilities that turn out to be useful for more than just battling in your daily life.
It's also produced several submissions to the Things Not To Do In A Pokeumans Base post on the kind of less responsible things people might get up to with the powers of a Pokemon and the mindset of the average teenager:
Just because you can breathe fire or fly does not mean you can post it on YouTube.
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.
"Solaere ssiun Hnaifv'daenn": A mighty D'deridex-class warbird, repurposed as an armed freighter delivering medical supplies. Justified in that the region is a little chaotic right now: The plague-ridden planet Glintara is no longer a member of the Romulan Star Empire, but they're independent from the Federation and Romulan Republic as well, and there's been sightings of Space Pirates in the area. And really, in the canon shows the Enterprise had to do that kind of cargo mission all the time.
Touhou fans love to depict various powers used for mundane or silly reasons. Even beyond all those mentioned in the Video Games subpage, 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.