Cengage Editing Page
Advanced editing exercsises
English for Everyone Paragraph Editing
Beginning to advanced; lots of paragraphs for editig practice.
Every day Edits
Learning English with Michelle
Lots of different editing points; scroll down for exercises
Editing and Proofreading Worksheets
English Grammar Extra WordsEng
Several exercises to find extra words (with answer key)
ESL Lounge Extra Words
More exercises to find extra words (with answer sheets)
Jon's English Proofreading Page
Lots of pdf exercises on a variety of editing topics.
Daily Grammar
This site has very short (as in 1-3 sentences) explanations anda then a short exercise. But it has every single grammar topic imagineable!
Using English for Academic PurposesUsing
Advanced site with proofreading overview and exercises.
Virtual Writing Tutor
Paste text into the editing box for grammar and spelling checking. Free account is limited to 500 words.
Grammarly
This is a Chrome add-on that checks grammar with onine writing.
My English Teacher.net Run-ons
Nice explanation with quiz (with answers)
Quia Run-ons practice