Any idea what PLUGIN is this SHARE-BAR?

That isn’t a WordPress site, but I’m pretty sure it’s “AddThis” sharing tools. https://www.addthis.com/get/sharing

The AddThis Sharing Tools (sidebar) was also included as a feature in this WordPress plugin: https://www.ads-software.com/plugins/addthis-smart-layers/

Take note of any WordPress version compatibility comments on the plugin page if/before you decide to try it.

thank you so much. I’ve it on my blog now. ??

You’re welcome!