Comparison chart of Google Forms, Socrative, Pear Deck, Nearpod, and Geddit. I would also encourage folks to checkout Class Flow, Infuse Learning, and Answer Pad.
"The Internet Archive, a 501(c)(3) non-profit, is building a digital library of Internet sites and other cultural artifacts in digital form. Like a paper library, we provide free access to researchers, historians, scholars, and the general public."
Nitro Reader lets you create PDF files, collaborate and review, fill and save forms, add text to pages, QuickSign™ documents, view PDF files in your Web browser, and more...