Renderkit
A collection of interfaces and classes for atomic behavior objects, with support for many compositional patterns.
Most of these classes can be used as "cfr plugins".
DQX Drupal modules
Menu editor
A UI to create a lot of menu links at once.
Views content DS
Easily bring Views displays into Display suite as fields.
Works nicely on taxonomy term pages. A nice alternative to TVI.
X Autoload
A class loader module to bring PSR-4 and friends to Drupal 7.