I think it would be cool if you added new types of rings in addition to the basic +Strength type of things.
Some examples could be a Ring of Slow Digestion, where you lose belly at a slower rate, or a Ring of Skill, where your skills do a little bit more damage (probably not a whole rank, maybe half a rank or so). These would, of course, have to be pretty rare (maybe Phoenix Down Armor rarity? I've only found that twice).