"list" plugin does not exist after upgrading from Drupal 8.3.x to 8.4.2
This is solved now. I think that there was a mismatch between the PHP/ Drush / Drupal 8.4.3 versions.

This confused me so I include a table below of what is now working for me. I used it as a checklist to ensure that I had both a dev Drupal 8.3.7 and a dev Drupal 8.4.3 running in parallel.

Despite what the documentation says I think Drush 8.1.15 is not suitable for Drupal 8.4.3 and yes, there are some Drush 9.0.0-rc1 commands that don't work as expected  - like dumping SQL and redirecting SQL files to drush sqlc -  but it is workable.

Bits and pieces in each of existing and future Drupal

               iMac               MacBook                
PHP VM         7.1.12             7.1.12              
PHP Host       7.1.12             7.1.12
Drush VM       8.1.16-dev         ~9.0     
Drush Host     8.1.15             ~9.0            
Drupal Core    8.3.7              8.4.3
MySQL          5.7.20             5.7.20   (Required MySQL 5.5.3/MariaDB 5.5.20)