ProWritingAid
This was recommended by one of my RedPenners and it's been on my Recommendations page for some time.
Within the Red Pen Editing cycle, step 9 is DRILL DOWN where, having addressed all other issues of structure, voice, tense, etc., we focus on paragraphs, sentences, words, and punctuation. It's the final sweep before sending our precious manuscript to our beta readers for feedback.
Step 9 relies on our understanding of spelling, grammar, and...