Is there a WordPress Plugin with a 'Share on Bluesky' Button?

Yes, there is a social share plugin for WordPress that has a button for Bluesky. It’s called Super Simple Social Share Icons by Volt Blocks.

Super Simple Social Share Icons is a lightweight plugin that allows users to easily add social share icons to their WordPress blog posts, including Facebook, X (Twitter), LinkedIn, Pinterest, WhatsApp and BlueSky.

Users can change the appearance of the icons, choose where they appear on blog posts, generate shortcode and edit the text that displays alongside the icons.