With the Field Conditional State module you can change the state of any supported fields form element depending on the content of other fields. This is done by providing an UI for Drupal's States API. All the changes made to a form by FCS (Field Conditional States) utilize only the States API and therefore are clientside only.

"This module provides an advanced Entity Reference widget that uses a view embedded in a modal dialog for selecting items. The view can be paginated and have exposed filters."

The Jammer module hides particular elements from edit forms, similar to the Simplify module. This module is mentioned on the revisioning module/s project page on Drupal.org.

A nice way to add placeholders to input fields. "This module auto-converts form input fields with space-hogging labels into compact mobile-friendly input fields, with placeholders that animate into much smaller labels the moment text is keyed in. "

"Maxlength allows you to set maximum length of any field on any form making use of the form API. This includes fields created using the UI. (Example: any text field on a node)

From the project page:

The gist: "This module extends the functionality of the core 'file' field, adding new capabilities to the file upload widget, and providing a new extendible field formatter for displaying lists of files."