Drupal 8

Linktipp: Create custom fields in Drupal 8

Guide on how to create custom field types in Drupal 8

Drupal 8 Entity reference blocks: restricted access (Eingeschränkter Zugriff)

You're referencing a Drupal 8 block via block reference but after saving the entity reference input field says "restricted access" (German: "Eingeschränkter Zugriff")? That's simple to solve... and "works as designed".

Linktipp: 6 Modules to avoid before Drupal 8 arrives

The name says it all. No more comments required.
I don't think you should take the points too serious but some tips are good. For example I didn't know the smart url.module before.

It's worth to have a look!