During the release of Tenchi Muyo! OVA 4 they would release some illustrations on the official website, usually to celebrate holidays. They would only be up for a day, so if you weren't quick to grab them they would disappear. The site where I got most of these doesn't have them posted anymore, so I decided I would post them here. As far as I know, this is the complete set. The first 11 were done by Okuda Hitoshi, who did the Tenchi Muyo! manga. Presumably the last 8 were done by Oda Takeshi, the character designer for OVA 4, but I don't know for sure.