香り: kaori. This category, like "sounds," doesn't appear on traditional renku charts, but some contemporary renku masters include the senses of smell and sound to encourage poets to break the habit of strictly visual thinking.
To be complete, let's also keep in mind taste and touch when brainstorming this category. And (why not?) a sixth sense might also possibly find its way into your poem if you so desire. Remember: it's your (in the collective sense) poem!