FitVids

This module uses the FitVids.js library for fluid width video embeds (e.g. flash video in <iframe>s). You don't need it for pure HTML5 videos.
It supports YouTube, Vimeo, Blip.tv and Kickstarter by default, and can use it with other video providers like Dailymotion or Viddler.

Smart Trim

Smart Trim implements a new field formatter for textfields (text, text_long, and text_with_summary, if you want to get technical) that improves upon the "Summary or Trimmed" formatter built into Drupal 7

Field Conditional States

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.

Field HTML trim

From the project page on d.o. "This module provides a neat solution for cutting off the text without taking any HTML tags into consideration. It uses a regular expression containing all the words of a trimmed textual representation of the field value to extract the wanted block of HTML."

Common HTMLawed settings

Here are some common settings for HTMLawed that can be used as a more lenient 'filtered html' format for trusted editors that need a simple WYSIWYG. This configuration allows images, which can be a security risk. If you don't understand the risk, then leave Drupal's defaults the way they are and perhaps try to work with the Full HTML format or use CSS classes and stylesheets.