for weapon/armor furniture you could add the Armory and Outfit Stations somewhere.

see the armory station has some weapons attached to it.



and you could add little crafting areas for Blacksmithing and Woodworking stations if you haven't already?
Seems fitting as you make weapons with those stations.


my woodworking area


Block and Axe, Chopping (i think from Plunder Skulls) and
Logs, Twice-Split (from Home Goods from Western Skyrim/Blackwood/High isle/Necrom).

and my blacksmith area




i used the Murkmire Kiln, Derelict (From Lilmoth home goods), put a brazier in it for fire, and put Tongs, Forge half into it.
and added Hammer, Forge beside it.

there's a Nirncrux bowl (from Craglorn achievement furniture) on the table beside the Kiln, could also add the Nirncrux urn (Luxury Furniture) which is fitting as it's a trait material for armor and weapons.

there's likely more little furnishings one could add of course.

Furnishings I've used as decorative weaponry in the weapons stall of my Elinhir Private Arena include the:

Decorative blade of woe from Gold Coast achievement vendor
Argonian pestle, bone (crafted - makes a good mace)
knife, carving (housing editor vendor)
cleaver, butchers (crafted)
orcish knife, kitchen (crafted)
rough knife, butcher (crafted)
tool, harvest scythe (from plunder skulls so you'll need to hit up guild traders for this)
chef's cleaver (cooking vendors)
dwarven centurion hammer, detached (lux vendor so hit up guild traders)
dwarven centurion blade, detached (lux vendor)
hammer, forge (crafted)
rough axe, practical (housing editor)
rough hatched, practical (crafted)
rough spear, fishing (furniture vendors)
rough rod, fishing (furniture vendors)
tool, pitchfork (housing editor)
tool, sickle (housing editor)
solitude skewer, twisted iron (crafted)

I used the target dummy from Clockwork City as a stand in for a suit of armor. Some of the crafted dwarf ones may also work for this. The outfit station and armory station both are pretty good too.