Shopstr.store and https://plebeian.market/ have book categories although not audiobooks strictly but may do. If you publish on shopstr that shows in the marketplace tab of a nostr client that supports it like amethyst without the need to publish separately.

nostr:nprofile1qqs8qy3p9qnnhhq847d7wujl5hztcr7pg6rxhmpc63pkphztcmxp3wgpz9mhxue69uhkummnw3ezuamfdejj7qgmwaehxw309a6xsetxdaex2um59ehx7um5wgcjucm0d5hsz9nhwden5te0dehhxarjv4kxjar9wvhx7un89uqaujaz any plans you guys expand Alexandria to audiobooks?