Hi Mani 

Thanks for posting in the Lucidchart Community! Unfortunately it's currently not possible to restore a custom shape library once it's deleted from the account. However if you used your custom shapes in a document those shapes will still be there after the shape library is deleted. You can then open the document at hand and add those custom shapes to a new or existing custom shape library. I understand this is not ideal but at least this could allow you to recover some of your custom shapes for future use in other documents. For more information about this please review our Shape Libraries article from the Lucidchart Help Center. 

While what you are trying to do is not currently supported in Lucidchart we are always looking for how we can make our product more useful and effective for our users and your feedback is the best way for us to do that. Would you mind adding your idea to our feature request form? Ideas submitted to this form are passed on to the product development team for their consideration.

Thanks for your request and I apologize for any inconvenience this causes you.