D8 to D8 migrate source plugin? Migrate Source


  The migration configuration entity always contains a source key. The
  value is an associative array containing the name of the plugin and
  the configuration of it. Only the plugin key-value pair is mandatory,
  some plugins might not have any configurations.

source:
  plugin: d6_node



Googling I see examples outhere that use d6_node and d7_node but what does one use to migrate nodes from d8 to d8?

Looking at the core/modules/node/src/Plugin/migrate/source folder there is no such thing as d8_node
The Drupal 8 migration module has been moved into core as explained in this issue. If you're using at least Drupal 8.6.x, you don't need to apply the patch.



Old answer:

I'm going out on a limb and say that currently there isn't one and it can only be done by creating a custom plugin. 

Just found this Drupal 8 migration (source), thanks Berdir &amp; Primsi.