Magento Migration, Magentoonetomagentotwo
This website provides the best support for migration from Magento1 to Magento 2, Magento1 support has no longer available from 30 June 2020 that implies there will be no longer any patches available for Magento 1, if any risky security issue arises etc related, there are no new releases Magento 1 theme and other extensions.