Developer

  • Metadata is copied
  • Production data is NOT copied
  • Good for unit tests and apex tests

Developer Pro

  • More storage than developer
  • Includes multiple developer sandboxes, depending on which edition of Salesforce you have for your production org.
  • Good for unit tests and apex tests

Partial Copy

  • Developer sandbox plus data that you define in a sandbox template
  • Good for feature tests and regression tests

Full

  • Copy your entire production org
  • Can refresh every 29 days
  • Good for testing external integrations
  • Great for staging and user-acceptance testing
  • Great for production debugging

https://help.salesforce.com/articleView?id=data_sandbox_environments.htm&type=0