Double post, because too many attachments:
Here's some weapons I ripped and converted to Openxcom graphics (with some creative liberties). Most of them are from ZDoom mods, made by various people whose names I sadly don't know. The golden turret-like cannon is from Contra.
EDIT: Upgraded a few sprites and added some new ones.
EDIT: Added a second sheet with more stuff. Again, these weapons (except for Terraria swords) were converted from various assets by zDoom community, I only did the conversion (which sometimes, though not often, required some serious spriting). If you want to use any of it, please contact me and I'll try to identify the original author.
There's a Lollipop Chainsaw chainsaw in this one.
EDIT: But wait, there's more!
As always, stolen and modified from zDoom community.
Edit: Changed one weapon in collection 3.