Which really starts paying off when his enemies begin using fire-ball attacks.
He also threatens the miniature armies with a vacuum at the start.
In Exoria, a Zelda fanfic which is set in modern times, rather than using a normal blade, Link uses a gunsword, a sword that folds back into a silenced handgun. The Valentine special forces also use gunswords as their standard weapon of choice.
In Talk Nerdy To Me, one of the most esoteric attempts on Lord Vetinari's life mentioned in the narrative involved the would-be assassin smuggling a feral cat into the palace in his pants. That worked out about as well as could be expected.
In Guardian, Lulu's infamous moogle doll is explained as her only childhood toy and the only possession she had between the orphanage, Ginnem's pilgrimage, and the Bevelle temple. Her ability to puppeteer it with magic is what gets Ginnem's attention in the first place, and Lulu's first use of it as an actual weapon occurs when she beans a wolf-monster to protect Yuna. (Not that it does much.)
In Wonderful, Emma's weapon is a mop. A tinkered, super-destructive mop called Wonder Mop. She's smashed tanks with it.
Kasumi, the main character of Kasumi's Epic Quest!!! uses rubber bands as her weapon of choice. They are apparently ridiculously powerful against Creepers. Though in the final battle she forgoes this weapon in favor of a preposterously massive flamethrower. Hey, she was fighting an army of books...
The RWBY Loops has Ruby Rose, who converts her pet Zwei into a War Corgi (which actually sticks) and later starts up a museum for weapons across the multiverse, presumably containing multiple instances of this trope.
Many in The Infinite Loops, but the most notable are the Patchamen, by virtue of not being Loopers (thus not having all the abilities of the immortal dimension-wandering Loopers) and yet still beating a villain to death with napkins (that they choose specifically for the humiliation factor).