Cardboard furniture is such a cool and eco-friendly option. I haven't used it personally, but I've read about it, and it seems like a fantastic choice, especially if sustainability is a priority.

Make sure to check out reviews from people who have hands-on experience with cardboard furniture. It's always helpful to get insights from real users to understand how well it holds up over time and its durability.

I'd also recommend considering the specific needs of your client. Cardboard furniture can be surprisingly sturdy, but it might not be the best fit for heavy daily use. If your client is looking for something long-lasting and robust, you might want to explore other materials too.

In terms of style, there's a surprising variety in cardboard furniture designs. Some pieces have a modern, minimalist vibe, while others can be quite artistic. I would say, explore different styles and see what resonates with your client's taste.

Lastly, if you're interested in specific brands or want to see some examples, I found this article on https://www.yankodesign.com/2021/08/26/cardboard-furniture-designs-that-prove-just-how-sustainable-versatile-and-easy-to-use-this-everyday-material-is/ that showcases some really creative cardboard furniture options. It might give you and your client some inspiration.

I hope this helps, and best of luck with your search. If you have any more questions, feel free to ask.