Antique anvils certainly have a following, and collector value.
When I was dabbling in old west memorabilia years ago, I learned a bit about anvils.
Condition and weight. How flat the top working surface still is, etc.
They can bring some pretty good money.
I know nothing about anvils, except I would like to own one. At an auction a few months ago and one sold there for $300. It was a pretty big one and seem, to me at least, to be in pretty good shape. I was hoping to maybe buy it for $50-$75, but they opened the bidding higher than that.