Just pulled up a few lists on Google, here are some options:
Sardines contain 325 mg of calcium per 3 ounces.
Pink salmon offers 181 mg of calcium per three ounces.
A half cup of collard greens has 178 mg of calcium.
One tablespoon of blackstrap molasses offers 172 mg of calcium.
Other types of greens, nuts, okra show up as being calcium rich food sources.