In search of...(please help)

[Frugalmax]

As Daeothar mentioned, the old GW flagellant kit is a good resource(perhaps pricey now but you might be able to find partial sprues on ebay or something)- years ago I made a prisoner for a Warhammer Quest game using that kit with a head swap, removing weapons, and adding chains (there are many chains on the sprue), which we counted as being armed with a flail. The wrists almost all have some sort of manacle or band around them where you can attach the chains, and it makes an easy spot to cut off hands and swap them with others.

I also like the idea per Pattus Magnus of using the Northstar Oathmark Goblin Slaves, though I'm not sure what their height is. Another kitbash idea (pure speculation- I don't own these guys) is the Oathmark Revenants sprue with different heads- the interesting thing is that while these are undead models, their arms, torsos, and legs all appear to be "whole"- though raggedy. It could look like they were captured soldiers from some different land.

Then there's these guys from Reaper, which wouldn't make a regiment, but could be characterful filler (minding that Reaper minis tend to be kind of huge these days): https://www.reapermini.com/search/prisoner/latest/07122

[Elbows]

Shame as my local store just ended their large 25%+ discount on their Old World stock...harumph..

The Reapers are a solid contender for simple cost/efficiency, though I despise removing the Bones USA (Siocast) bases, as they tend to snap the feet off...

EDIT: Ordered four packs of the Reaper ones - see how I get on with that.  I think I can make six bases with the Dwarfs/Hobgoblins guarding them.

[Frugalmax]

Looking forward to seeing how they turn out!

[Khusru2]

I found these on Eureka

https://eurekaminusa.com/collections/colonials-african-captives-slaves-28mm