The following database tables have been deprecated as of Gravity Forms 2.3, and should not be utilized by any custom code or third-party plug-ins etc.
wp_rg_form
wp_rg_form_meta
wp_rg_form_view
wp_rg_incomplete_submissions
wp_rg_lead
wp_rg_lead_detail
wp_rg_lead_detail_long
wp_rg_lead_meta
wp_rg_lead_notes
For more detail on the Gravity Forms 2.3 upgrade process, refer to this article.