It's an interesting topic. One of my favorite collecting themes is "captives" on Roman coins. The iconography, but mainly the sociological and historical context (my research/teaching interests were sociology of violence, history of knowledge). So I'd be curious to learn what someone who studies modern slavery (i.e., recent centuries) finds interesting & important to understand about slavery in the ancient world.
I've never tried to find the manacles/shackles on the private market, but there have been various archaeological finds of human remains still bound, so you can see what the technology of restraint and captivity was. For example, a 2021 article in Smithsonian Magazine on a British Roman bound captive unearthed [
LINK]
Roman artworks and decorations depicting slaves/captives seem to have been reasonably abundant. Oil lamps and small bronze figurines especially seem to have survived to the present. I suppose some of these may have been used in the homes and daily lives of ordinary Romans?
Two Attached Images: (1) pair of Roman bronze statuettes of bound captives in museums (public domain images from Wikipedia); (2) pair of Roman oil lamps depicting "barbarians" / "captives" (from the decades-old catalog of a defunct Swiss firm).
Some here have published on the topic, both about the relevant coins and other antiquities. An interesting article on bronze barbarian/captives figures by someone who posts here: József Géza Kiss, 2021, "Bound in bronze – a Roman bronze statuette of a barbarian prisoner" [
LINK]. An article about the related topic of warfare with barbarians being depicted (for the late Roman "captives" imagery, you'd have to look at the book): Shawn Caza, 2019, "Back in the saddle again: a re-examination of the FEL TEMP REPARATIO Falling horseman type" [
LINK].
I won't go on about more academic articles & scholarly books on the topic -- unless anyone else does. (I'm always up for it, and would certainly like to learn more.)
My Forum Gallery of Barbarians & Captives on Roman coins [
LINK]
My "Barbarians, Captives, and Enemies" Collection page [
LINK]