There's a big buffet consisting of mostly vegan and a few ovo-lacto options. All items are clearly marked for being vegan or containing dairy/ovo contents or allergens. Pretty much everything is organic. The staff is friendly, the drink options are very good.
I ended up eating there three times over the weekend I spent in Basel because I liked the food so much. The food seems expensive, but Basel is a very expensive place anyway. Compared to the general pricing in the city, Tibits is not expensive at all, especially regarding the quality of the food. Very highly recommended.