Can be anything from any source, movies, books, comics, video games, manga, anime etc.
Pic related is mine, the dragonslayer from berserk. I like it because it's simple. It's just a big fucking sword, no fancy bells and whistles like enchantments or spells.
Second runner-up is sting from lord of the rings, I like that it glows blue when orcs are around and it can be used in the dark as a light source.
Roland's revolvers from The Dark Tower. Forged from the melted steel of Excalibur. I really hope the next adaptation they're doing will be good