Black pudding (blood sausage) would be my pick, but there are also a lot of good Chinese recipes that include pork blood curd.

The only danger I am aware of--beyond the risks of eating pork products in general--is iron overdose, which means you have to ration your consumption appropriately.

The viscera may also be used, though not necessarily for food. Whatever cannot be eaten can likely be turned into glue, leather, fertilizer, string, etc.