JA K2 to com content migration plugin is a Joomla plugin to migrate K2 content to Joomla comcontent in one go. It can convert all K2 elements: K2 categories, K2 Items, K2 Extra fields group, K2 extra fields, K2 tags. For K2 extra field, you can rename it if necessary. Each extra field group when converted to comcontent will be a new content type, you can add new items for any content type.
Please note : The installation will install 3 plugins in total, the other two are required for completing migration of K2 to com content.
Please read the documentation before migrating.
https://www.joomlart.com/member/downloads/joomlart/joomla-extensions/ja-k2-data-migration-plugin