I should probably stop buying stuff that I don't know what it is. Sometimes I can't resist. I thought I'd throw them on here because I know somebody here is probably going to know it instantly. But there's a bunch of them.
Blank rounds. Those that have dimples (firing pin impression) on the primer are spent (fired). Any that do not have a dimple may still be live (unfired primer + powder). Pretty cool with the links attached.
linked brass will always sell. Not sure on ebay, they are nuts on gun related stuff. IF ebay is your only option, you might have better luck pulling the brass and selling just the links.
.308 blanks. Don't try to sell them on ebay, I got my account suspended and an infraction for selling rusty spent steel bullet shells for arts and crafts.