You might have the best content on your blog but with poor quality of content your message will not reach to your reader in an effective way. There are several quality control plugins for your content which are useful to provide improvement of the quality of the blog content in various sense like correct spelled words, mange post ideas etc.
Genki Pre-Publish Reminders
Genki Pre-Publish Reminder display a pre-publish reminder tasklist on the Posts Admin Panel. It places a text box on your post editing page which allows you to insert your signature.
Post Ideas keeps track of all your blog article or post ideas mentioning a working title, related keywords, links of sources and descriptions. It mange post ideas, sort ideas by name, priority or date.
AJAX Spell Checker
AJAX Spell Checker includes the ability to show incorrectly spelled words, list suggested words from the dictionary, and allow new words to add in custom dictionary. The Spell Checker works well in Firefox, Internet Explorer, Opera and Safari.