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.
the kirkhammer from Bloodborne is one of my favorites! pretty much all of the weapons in Bloodborne are all-around fantastic but the kirkhammer specifically is the one I had the most fun with and I love it's design