There are a lot of changes between Drupal 7 and Drupal 8. Two of my contributed modules, facebook_boxes and mp3 player, will change dramatically due to the various changes. I propose a session to go over the changes between those two, focusing on the new block and file_field plug in API's. This would be a session which shows the techniques used for Drupal 7 and how the convert to Drupal 8. A third possible module to go over (time permitting) could be the smart_trim module, which extends the fieldFormatter, but was contributed through the community (thanks @pferlito)