Some nice items to be available in Stendhal would be rings that prevent poisoning. These rings should have a very low defense (if any at all) to discourage being used as a defensive item and should be somewhat rare, especially the more powerful ones, to maintain the in-game economy. Here are some examples:
Medicinal ring: Reduces chance of poisoning by 25%, DEF=0
Antivenom ring: Reduces chance of poisoning by 50%, DEF=0
Antitoxin ring: Nullifies chance of poisoning, DEF=1
If you would like to use the example ring images attached they are released under a BSD license. Stendhal and its authors are free to use them however they wish.