DoubelJ

With this plugin you can add a Training and associated Courses to your WordPress site. 
With a widget you can get a sorted list by date of the Training.
In newer versions there is an agenda with the training and an opportunity to add subscription forms at the training and an e-learning module.

JaJaDi Training

With this plugin you can add training and courses to your WordPress site.

Gregory Karpinsky (@tivnet)

This plugin is a part of TIVWP Academia series. It demonstrates how a plugin can check for prerequisites and notify administrator.

TIVWP-DEMIA Check prerequisites

This plugin is a part of TIVWP Academia series.

JaJaDi Training vs TIVWP-DEMIA Check prerequisites