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.
That man-portable Gatling gun with an integrated shoulder-fired rocket launcher from the Flash game Combat Instinct 3.
It just has this over-the-top early 2000s sci-fi games feel to it, pay no mind to how unwieldy and cumbersome a weapon like this would actually be, let alone without a futuristic full-body exo suit.