Doc to Form and Save as Doc are similar in that they both help you convert information in one type of Google file to another type.
Doc to Form, as it says, helps me easily convert questions written on a Google Doc to a Google Form ready for people to fill out and answer. Late last week our school nurse asked me if I could transform the quiz teachers have to take about blood borne pathogens and convert it to a Google From. She sent me a Word file. I uploaded it to Google Drive and used Doc to Form to make the transformation process faster. This tutorial video shows you how it works in about 90 seconds. Doc to Form is free for up to 10 questions. If you need more, there is a really easy process to donate $3 to the developer via paypal and use up to 50 questions. (I highly recommend donating, and I have no financial stake in that suggestion.)
I know I'll be using both of these a lot to make forms and documents from docs and spreadsheets.