The bolter and heavy bolter from Warhammer 40,000: Space Marine, maybe even a Stalker Bolter and a Melta Gun type weapon.
A tiny gatling based SMG
An incendiary cannon that shoots impact detonated firebombs made from empty sarsaparilla bottles, flamer fuel and powder charges
A plasma based flame throw, that uses Microfusion cells at an alarming rate but deals masive CQC damage and has a badass green flame
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Call it something badass too, like the Immolater
A weapon that uses Psyconic fields to asplode heads in a very ridiculous and over the top way. (wild wasteland exclusive gun)