Most spices and herbs that are antioxidant are usually also bacteriostatic. The herbs and spices highest in antioxidant content includes clove, allspice, peppermint, clinnamon as noted above, oregano and thyme. I'm not sure about the bacteriostatic properties of these, but I'd be willing to give them a try. Some of the others (also used in curing meats) are garlic, ginger and nigella.
The only pro-oxidant one that I remember is marjoram and I'd never use it in cured sausages.
Somewhere I had a list but since I don't remember what I named it, I can't find it on my hard drive. Sorry.