I tried, this is what I came up with under significant time pressure:

Happy books sound great.

It was very difficult to think of a plural verb with 5 letters, and once I realized that was an issue, I was worried that I wouldn't have enough time to come up with a singular noun that would fit any of the singular verbs that I was considering (reads, seems).

Interestingly, this is the exact same mistake that ChatGPT made! It has "spell" -> "spells" which is a plurality / correctness of sentence mistake.

My sentence is technically correct and could be used plausibly in conversation: "What kind of books do you want to read?" "Happy books sound great."

But it's a pretty weak sentence. Being restricted from articles makes it very difficult to get agreement.