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.
i liked the soul stealing chaos runesword from the Elric series
Gonna second this. It's surprisingly underrated, but so is Michael Moorcock, much to his seething.
one day someone will appreciate comrade Moorcock and his very online self