D6 to D8 migrate new content I did a D6 to D8 migration in 10/2015 and I recreated the blocks and views not migrated.  But in the mean time 6 month later my D6 original site has been getting more content.

What is the best way to bring all of that content from the last 6 month from my D6 to my migrated D8?
You should use migrate module, it's in drupal8's core.

You can define migrations for blocks, nodes, comments, users ... and launch then when you need.

You can select "update" option to syncronize imported content on your new site with changed content on old site.

Here's the offical doc of migrate:
https://www.drupal.org/migrate